hammer vs sledgehammer

hammer and sledgehammer both are nouns.

Word	Noun	Adjective	Verb	Adverb
hammer	Yes	No	Yes	No
sledgehammer	Yes	No	Yes	No

As nouns, sledgehammer is a hyponym of hammer; that is, sledgehammer is a word with a more specific, narrower meaning than hammer:

hammer: a hand tool with a heavy rigid head and a handle; used to deliver an impulsive force by striking
sledgehammer: a heavy long-handled hammer used to drive stakes or wedges

As verbs, sledgehammer is a hyponym of hammer; that is, sledgehammer is a word with a more specific, narrower meaning than hammer:

Other hyponyms of hammer include sledge.

hammer (noun)	sledgehammer (noun)
the act of pounding (delivering repeated heavy blows)	a heavy long-handled hammer used to drive stakes or wedges
a hand tool with a heavy rigid head and a handle; used to deliver an impulsive force by striking
a power tool for drilling rocks
a striker that is covered in felt and that causes the piano strings to vibrate
a light drumstick with a rounded head that is used to strike such percussion instruments as chimes, kettledrums, marimbas, glockenspiels, etc.
the part of a gunlock that strikes the percussion cap when the trigger is pulled
a heavy metal sphere attached to a flexible wire; used in the hammer throw
the ossicle attached to the eardrum

hammer (verb)	sledgehammer (verb)
beat with or as if with a hammer	beat with a sledgehammer
create by hammering