harpoon vs grab

harpoon and grab both are nouns.

Word	Noun	Adjective	Verb	Adverb
harpoon	Yes	No	Yes	No
grab	Yes	No	Yes	No

As verbs, grab is a hypernym of harpoon; that is, grab is a word with a broader meaning than harpoon:

Other hypernyms of harpoon include catch.

harpoon (noun)	grab (noun)
a spear with a shaft and barbed point for throwing; used for catching large fish or whales; a strong line is attached to it	the act of catching an object with the hands
	a mechanical device for gripping an object

harpoon (verb)	grab (verb)
spear with a harpoon	capture the attention or imagination of
	take hold of so as to seize or restrain or stop the motion of
	take or grasp suddenly
	make a grasping or snatching motion with the hand
	get hold of or seize quickly and easily
	obtain illegally or unscrupulously