flummox

Etymology

Uncertain, probably risen out of a British dialect (OED finds candidate words in Herefordshire, Gloucestershire, southern Cheshire, and Sheffield). "The formation seems to be onomatopœic, expressive of the notion of throwing down roughly and untidily" [OED].

verb

1. (intransitive) To confuse; to fluster; to flabbergast.
   With United's movement flummoxing the visitors, Berbatov saw his low shot saved well by Ben Foster on his first return to Old Trafford. January 22, 2011, “Man Utd 5 - 0 Birmingham”, in BBC
2. (intransitive, uncommon) To give in, to give up, to collapse.