muster up vs summon

muster up and summon both are verbs.

Word	Noun	Adjective	Verb	Adverb
muster up	No	No	Yes	No
summon	No	No	Yes	No

As verbs, muster up and summon are synonyms defined as:

Other synonyms of muster up include come up, muster, rally.

muster up (verb)	summon (verb)
gather or bring together	make ready for action or use
	call in an official matter, such as to attend court
	ask to come
	gather or bring together
	cause to become available for use, either literally or figuratively