work on vs tool

work on is not a noun while tool is a noun.

Word	Noun	Adjective	Verb	Adverb
work on	No	No	Yes	No
tool	Yes	No	Yes	No

As verbs, tool is a hyponym of work on; that is, tool is a word with a more specific, narrower meaning than work on:

Other hyponyms of work on include hot-work, cold work, coldwork, overwork, make over, retread, rework, rack, till.

work on (noun)	tool (noun)
	the means whereby some act is accomplished
	an implement used in the practice of a vocation
	obscene terms for penis
	a person who is controlled by others and is used to perform unpleasant or dishonest tasks for someone else

work on (verb)	tool (verb)
shape, form, or improve a material	work with a tool
to exert effort in order to do, make, or perform something	ride in a car with no particular goal and just for the pleasure of it
	drive
	furnish with tools