gig vs ship's boat

gig and ship's boat both are nouns.

Word	Noun	Adjective	Verb	Adverb
gig	Yes	No	No	No
ship's boat	Yes	No	No	No

As nouns, ship's boat is a hypernym of gig; that is, ship's boat is a word with a broader meaning than gig:

Other hypernyms of gig include cutter, pinnace, tender.

gig (noun)	ship's boat (noun)
a booking for musicians	a boat for communication between ship and shore
small two-wheeled horse-drawn carriage; with two seats and no hood
tender that is a light ship's boat; often for personal use of captain
long and light rowing boat; especially for racing
an implement with a shaft and barbed point used for catching fish
a cluster of hooks (without barbs) that is drawn through a school of fish to hook their bodies; used when fish are not biting