aid vs improve

aid is a noun but improve is not a noun.

Word	Noun	Adjective	Verb	Adverb
aid	Yes	No	Yes	No
improve	No	No	Yes	No

As verbs, improve is a hypernym of aid; that is, improve is a word with a broader meaning than aid:

Other hypernyms of aid include ameliorate, amend, better, meliorate.

aid (noun)	improve (noun)
the activity of contributing to the fulfillment of a need or furtherance of an effort or purpose
the work of providing treatment for or attending to someone or something
a person or thing that is a resource that helps make something easier or possible to do
gift of money or other material help to support a person or cause

aid (verb)	improve (verb)
improve the condition of	get better
give help or assistance; be of service	to make better