From BiblePortal Wikipedia

Vine's Expository Dictionary of NT Words [1]

A — 1: Καιρός (Strong'S #2540 — Noun Masculine — kairos — kahee-ros' )

primarily, "a due measure," is used of "a fixed and definite period, a time, season," and is translated "opportunity" in  Galatians 6:10;  Hebrews 11:15 . See Season , Time , While.

A — 2: Εὐκαιρία (Strong'S #2120 — Noun Feminine — eukairia — yoo-kahee-ree'-ah )

"a fitting time, opportunity" (eu, "well," and No. 1), occurs in  Matthew 26:16;  Luke 22:6 . Cp. eukairos, "seasonable;" see Convenient.

A — 3: Τόπος (Strong'S #5117 — Noun Masculine — topos — top'-os )

"to place," is translated "opportunity" in  Acts 25:16 , RV (AV, "licence"). See Place , Room.

B — 1: Εὐκαιρέω (Strong'S #2119 — Verb — eukaireo — yoo-kahee-reh'-o )

"to have time or leisure" (akin to A, No. 2), is translated "he shall have opportunity" in  1—Corinthians 16:12 , RV (AV, "convenient time"). See Leisure.

B — 2: Ἀκαιρέομαι (Strong'S #170 — Verb — akaireomai — ak-ahee-reh'-om-ahee )

"to have no opportunity" (a, negative, and kairos, "season"), occurs in  Philippians 4:10 .

King James Dictionary [2]

OPPORTU'NITY, n. L. opportunitas.

1. Fit or convenient time a time favorable for the purpose suitable time combined with other favorable circumstances. Suitableness of time is the predominant signification, but it includes generally circumstances of place and other conveniences adapted to the end desired.

A wise man will make more opportunities than he finds.

I had an opportunity to see the cloud descent.

Neglect no opportunity of doing good.

2. Convenient means. I had an opportunity of sending the letter, or no opportunity to send it. Opportunities rarely occur on frequently offer.

Webster's Dictionary [3]

(1): ( n.) Convenience of situation; fitness.

(2): ( n.) Fit or convenient time; a time or place favorable for executing a purpose; a suitable combination of conditions; suitable occasion; chance.

(3): ( n.) Importunity; earnestness.