Meaning of GIANTS

The Old Testament frequently speaks of ancient men whose physical strength and height earned them the name "giants," a translation of three Hebrew terms:

(a) "Nephilim."
Etymologically it means fallen beings, beings in front of whom one falls in admiration, or "men of renown."
According to Greco-Latin mythology, giants were fabulous beings, children of the Earth and Tartarus, who sought to climb the sky in their fury against the gods. But "nephilim" does not imply great stature even in Gen. 6:4 nor in Num. 13:33, the only texts in which they are mentioned.

The phrases "we saw giants there...", "we were like locusts" are hyperbole to express the fear they caused them.
(b) Gibborim.

It means "the strong" or "the heroes." The giant translation is not justified.
(c) The "rephaim."

This is the exact equivalent of "giants" and refers to certain ancient inhabitants of Canaan (2 Sam. 21:15-16, 20-22; 1 Chron. 20:4, 6, 8). Even in the days of David we have them in Gath, among the Philistines.

A geographical name, the valley of the "Rephaim", near Jerusalem, indicates at least its passage in that direction (Josh. 15:8; 2 Sam. 5:18). The data provided in Gen. 14 and confirmed by Deut. 2:10-26 go back to a very ancient time.

It is likely that Palestine was populated by the "rephaim" before the entry of the Canaanites, in the third millennium BC. Goliath was racially one of the "rephaim", although, politically, a philistine. He was about 2'60 m tall. Tall; Og's bed (another of the famous giants) measured about 3.50 m. in length. After David there is no mention of the “rephaim” giants.