Charles Ellicott Commentary Genesis 49:21

"Naphtali is a hind let loose: He giveth goodly words." — Genesis 49:21 (ASV)

Naphtali.—Gad had been described as moving slowly in war, and allowing himself to be surprised by hordes of plunderers, whom, nevertheless, as soon as he has collected his forces, he repels and pursues with vigour. Naphtali, on the contrary, is light and active, moving rapidly like a hind let loose; or, literally, sent forth, like the scouts or van of an army. And thus he brings back goodly words—Hebrew, words of pleasure—that is, trustworthy intelligence to guide the army in its movements.

Another translation has been proposed, which has the support of the Septuagint: Naphtali is a spreading terebinth, which shoots forth goodly branches. It retains the consonants of the Hebrew text but gives them different vowels.