the bollocks, the dog's bollocks, something excellent
verb (usually foll by up)
5.
to muddle or botch
Usage note
Both its anatomical senses and its various extended senses nowadays have far less impact than they used to, and seem unlikely to cause offence, though some older or more conservative people may object. The fact that shops displaying the Sex Pistols' album containing this word were charged with offences defined in 19th-century Indecent Advertisement and Vagrancy Acts now seems hard to credit
Word Origin
Old English beallucas, diminutive (pl) of beallu (unattested); see ball1
Word Origin and History for bollix
v.
"bungle," respelling (perhaps euphemistic) of bollocks, plural of bollock "testicle," from Old English beallucas "testicles," from Proto-Germanic *ball-, from PIE *bhel- (2) "to inflate, swell" (see bole). Related: Bollixed; bollixing.