underachieve vs underperform

underachieve and underperform both are verbs.

Word	Noun	Adjective	Verb	Adverb
underachieve	No	No	Yes	No
underperform	No	No	Yes	No

As verbs, underachieve and underperform are synonyms defined as:

underachieve and underperform: perform less well or with less success than expected

underachieve (verb)	underperform (verb)
perform less well or with less success than expected	perform too rarely
	perform less well or with less success than expected