skiff vs small boat

skiff and small boat both are nouns.

Word	Noun	Adjective	Verb	Adverb
skiff	Yes	No	No	No
small boat	Yes	No	No	No

As nouns, small boat is a hypernym of skiff; that is, small boat is a word with a broader meaning than skiff:

skiff: any of various small boats propelled by oars or by sails or by a motor
small boat: a boat that is small

skiff (noun)	small boat (noun)
any of various small boats propelled by oars or by sails or by a motor	a boat that is small