From BiblePortal Wikipedia

Vine's Expository Dictionary of OT Words [1]

Shâkach ( שָׁכֵחַ , Strong'S #7911), “to forget.” The common word meaning “to forget” appears in all periods of the Hebrew language; this term is also found in Aramaic. It occurs just over 100 times in the Hebrew Bible. Shâkach is found for the first time in the Old Testament in Gen. 27:45, when Rebekah urges Jacob to flee his home until Esau “forget that which thou hast done to him.”

As the people worshiped strange gods, Jeremiah reminded Judah that “all thy lovers have forgotten thee; they seek thee not” (Jer. 30:14). But God does not “forget” His people: “Can a woman forget her suckling child, that she should not have compassion on the son of her womb? yea, they may forget, yet will I not forget thee” (Isa. 49:15). In spite of this, when destruction came, Judah complained: “Wherefore dost thou forget us for ever …?” (Lam. 5:20). Israel would often “forget” God’s law (Hos. 4:6) and God’s name (Jer. 23:27).

King James Dictionary [2]

FORGET', pret. forgot. forgat, obs.

1. To lose the remembrance of to let go from the memory.

Bless the Lord, O my soul, and forget not all his benefits.  Psalms 103 .

2. To slight to neglect.

Can a woman forget her sucking child? Yea, they may forget, yet will I not forget thee.  Isaiah 49 .

Webster's Dictionary [3]

(1): ( v. t.) To lose the remembrance of; to let go from the memory; to cease to have in mind; not to think of; also, to lose the power of; to cease from doing.

(2): ( v. t.) To treat with inattention or disregard; to slight; to neglect.