vex vs vexation

vex is not a noun while vexation is a noun.

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

vex (noun)	vexation (noun)
	the act of troubling or annoying someone
	something or someone that causes anxiety; a source of unhappiness
	anger produced by some annoying irritation
	the psychological state of being irritated or annoyed

vex (verb)	vexation (verb)
be a mystery or bewildering to
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