Definitions for bang-up
Random House Webster's College Dictionary
Origin of bang-up:
bang-up, bully, corking, cracking, dandy, great, groovy, keen, neat, nifty, not bad(p), peachy, slap-up, swell, smashing(verb)
"he did a bully job"; "a neat sports car"; "had a great time at the party"; "you look simply smashing"
bang up, smash up, smash(verb)
damage or destroy as if by violence
"The teenager banged up the car of his mother"
impregnate, knock up, bang up, prang up(verb)
"He impregnated his wife again"
Especially good; wonderful; superb.