I. mus ‧ ter 1 /ˈmʌstə $ -ər/ BrE AmE verb
[ Date: 1300-1400 ; Language: Old French ; Origin: monstrer , from Latin monstrare 'to show' ]
1 . [transitive] ( also muster up something ) to get enough courage, confidence, support etc to do something, especially with difficulty SYN summon (up)
muster (up) the courage/confidence/energy etc to do something
Finally I mustered up the courage to ask her out.
Senator Newbolt has been trying to muster support for his proposals.
‘It’s going to be fine,’ replied David, with as much confidence as he could muster.
2 . [intransitive and transitive] if soldiers muster, or if someone musters them, they come together in a group SYN gather :
In April 1185, he began to muster an army.
II. muster 2 BrE AmE noun
1 . pass muster (as something) to be accepted as good enough for something:
I wasn’t sure that our clothing would pass muster at the club door.
2 . [countable] literary a gathering together of soldiers so that they can be counted, checked etc