nail vs apprehend

nail is a noun but apprehend is not a noun.

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

As verbs, nail and apprehend are synonyms defined as:

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

nail (noun)	apprehend (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

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