vex vs hassle

vex is not a noun while hassle is a noun.

Word	Noun	Adjective	Verb	Adverb
vex	No	No	Yes	No
hassle	Yes	No	Yes	No

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

vex (noun)	hassle (noun)
	disorderly fighting
	an angry disturbance

vex (verb)	hassle (verb)
be a mystery or bewildering to	annoy continually or chronically
subject to prolonged examination, discussion, or deliberation
change the arrangement or position of
cause annoyance in; disturb, especially by minor irritations
disturb the peace of mind of; afflict with mental agitation or distress