apprehend vs nail

apprehend is not a noun while nail is a noun.

Word	Noun	Adjective	Verb	Adverb
apprehend	No	No	Yes	No
nail	Yes	No	Yes	No

As verbs, apprehend and nail are synonyms defined as:

Other synonyms of apprehend include arrest, collar, cop, nab, pick up.

apprehend (noun)	nail (noun)
	a thin pointed piece of metal that is hammered into materials as a fastener
	horny plate covering and protecting part of the dorsal surface of the digits
	a former unit of length for cloth equal to 1/16 of a yard

apprehend (verb)	nail (verb)
get the meaning of something	complete a pass
take into custody	attach something somewhere by means of nails
anticipate with dread or anxiety	take into custody
	hit with great force
	locate exactly
	succeed at easily
	succeed in obtaining a position