absobloodylutely/absofuckinglutely - an exclamation as to resound a definite yes.
ace - excellent, great. A rather out of vogue term, probably still used by kids.
Adam and Eve - Rhyming Slang for 'believe', e.g. "Would you Adam and Eve it mate!".
afters - short for the term 'after hours' meaning drinking in a pub after official closing time. Also see 'lock-in'.
aggro - short for aggravation or violence, e.g. "He was steaming drunk and well up for some aggro".
Alan Whicker(s) - Rhyming Slang for 'knickers'.
all over the gaff/shop - general term to describe someone or something that has no direction or that is in a mess.
allright/awright - a greeting literally meaning "is everything all fine?". Usually used in the form "awright mate!".
Annabel Giles - Modern Rhyming Slang for 'piles' (haemorrhoids).