grappling hook vs grapnel

grappling hook and grapnel both are nouns.

Word	Noun	Adjective	Verb	Adverb
grappling hook	Yes	No	No	No
grapnel	Yes	No	No	No

As nouns, grappling hook and grapnel are synonyms defined as:

grappling hook and grapnel: a tool consisting of several hooks for grasping and holding; often thrown with a rope

Other synonyms of grappling hook include grapple, grappler, grappling iron.

grappling hook (noun)	grapnel (noun)
a tool consisting of several hooks for grasping and holding; often thrown with a rope	a light anchor for small boats
	a tool consisting of several hooks for grasping and holding; often thrown with a rope