From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

Maranatha An Aram. [Note: Aramaic.] expression which occurs in   1 Corinthians 16:22 in juxtaposition with ‘anathema’ (‘If any man loveth not the Lord, let him be anathema. Maran atha’ [so RV [Note: Revised Version.] ]).

1. Meaning of the term . The original meaning of the term has been disputed, but it is now generally agreed that it is a component of two distinct words (cf. RV [Note: Revised Version.] above). Most moderns follow Bickell in holding that the two parts of which the expression is composed mean ‘Our Lord, come I’ (= Aram. [Note: Aramaic.] mâranâ thâ ). This seems preferable to the older view, according to which the meaning would be ‘Our Lord has come I’ (= Aram. [Note: Aramaic.] mâran ’athâ ). The imperative sense is made probable by   Revelation 22:20 (’Amen. Come, Lord Jesus!’), from which it may perhaps be inferred that some such formula as ‘O our Lord, or O Lord, come!’ was in use in early Christian circles. A very early instance of the use of the term occurs in the Didache at the end of the Eucharistic prayer (ch. 10).

The passage runs as follows:

‘Let grace come, and this world pass away.

Hosanna to the God of David.

If any is holy, let him come: if any is not, let him repent.

Maranatha. Amen.’

Here the combination maranatha. Amen (= ‘O our Lord, come! Amen’) is strikingly parallel with the remarkable phrase in   Revelation 22:20 (‘Amen. Come, Lord’). It is noticeable also that in both passages the expression is used as a concluding formula. Whether any similar formula was in use among the Jews is disputed. An old Jewish acrostic hymn, still extant in all types of the Jewish liturgy, the initial letters of the lines of which may be read ‘Amen. Come’ (Heb. âmçn bô ) at least suggests the possibility of such a usage.

2. Original significance of the expression . It is clear from the passage in the Didache cited above that ‘Maranatha’ cannot be regarded as a formula of excommunication synonymous with ‘anathema’ (so Calvin, comparing ‘Abba, Father’). It was rather a watchword of the earliest Christian community, embodying the thought in the form of a prayer that the ‘Parousia,’ or Second Advent of the Lord, might soon be consummated, in accordance with the ardent expectations current in the first generation.

3. Later usage. In later usage, under the influence of false exegesis, the term acquired an imprecatory sense. It thus occurs in an early sepulchral inscription (4th or 5th cent.) from the island of Salamis. Its supposed correspondence with the Jewish shammatha (the 3rd or highest degree of excommunication) has, of course, nothing to substantiate it. Further details of this development will be found in Hastings’ DB [Note: Dictionary of the Bible.] , s.v . ‘M ranatha.’

G. H. Box.

Hawker's Poor Man's Concordance And Dictionary [2]

We meet with this word joined to Anathema,  1 Corinthians 16:22. See Anathema Maranatha. In addition to what was then observed under this head, it may not be improper to remark yet farther, that when the apostle Paul useth this form of expression, which signifies, Let the offender that loves not the Lord Jesus Christ be punished when the Lord comes, he useth it not as a matter that was new, or a form that was never heard of before, but rather one well known. It should seem to be rather a proverbial method of saying, let a man that is guilty of such and such things be an Anathema Maranatha. It is as if the person so pronouncing the punishment meant thereby to say, it exceeds my power to express what ought to be the consequence of your crime, I therefore leave you to the Lord when he comes.

Webster's Dictionary [3]

(n.) "Our Lord cometh;" - an expression used by St. Paul at the conclusion of his first Epistle to the Corinthians (xvi. 22). This word has been used in anathematizing persons for great crimes; as much as to say, "May the Lord come quickly to take vengeance of thy crimes." See Anathema maranatha, under Anathema.

Smith's Bible Dictionary [4]

Maranath'a. An Aramaic or Syriac expression used by St. Paul at the conclusion of his first Epistle to the Corinthians,  1 Corinthians 16:22, signifying "Our Lord Cometh".

Morrish Bible Dictionary [5]

Two Aramaic words signifying, 'the Lord cometh,' added (perhaps as a kind of watchword) after the word Anathema, 'let him be accursed,' applied to those who love not the Lord Jesus.  1 Corinthians 16:22 .

King James Dictionary [6]

MARANA'THA, n. The Lord comes or has come a word used by the apostle Paul in expressing a curse. This word was used in anathematizing persons for great crimes as much as to say, "may the Lord come quickly to take vengeance on thee for thy crimes."

Holman Bible Dictionary [7]

 1 Corinthians 16:22 1 Corinthians 13:1 anathema Anathema

People's Dictionary of the Bible [8]

Maranatha ( Măr'A-Năth'Ah ). An Aramaic expression signifying "Our Lord will come."  1 Corinthians 16:22.

Easton's Bible Dictionary [9]

 1 Corinthians 16:22 Philippians 4:5 James 5:8,9

American Tract Society Bible Dictionary [10]

Composed of two Syriac words, signifying "the Lord cometh." See Anathema .

Watson's Biblical & Theological Dictionary [11]

See Anathema .

International Standard Bible Encyclopedia [12]

mar - a - nath´a , mar - an - a´tha (from Aramaic words, אתה מרנא , mārānā' 'āthāh , "Our Lord cometh, or will come"; according to some, "has come"; to others, "Come!" an invitation for his speedy reappearance (compare   Revelation 22:20 ); μαραναθά , maranathá , or μαρὰν ἀθά , marán athá ): Used in connection with ἀνάθεμα , anáthema , "accursed" ( 1 Corinthians 16:22 ), but has no necessary connection therewith. It was used by early Christians to add solemn emphasis to previous statement, injunction or adjuration, and seems to have become a sort of watchword; possibly forming part of an early liturgy.

The Nuttall Encyclopedia [13]

The Lord cometh to judge), a form of anathema in use among the Jews.

Kitto's Popular Cyclopedia of Biblial Literature [14]

Marana´tha [ANATHEMA]