While the word wanker is a more general and term for expressing disdain for somebody, the word LAF describes a person with a tendency to show off or brag in an excessive and embarrassing way.
LAF can also be used as alternative assignment of feminine behaviour.
"well at first i thought this guy delivers, but in the end he was just another laf."
"don't be such a LAF, come and drink with the boys"
SAYS SHE HAS MONEY BUT NO ONE HAS SEEN IT VEEEERY INTERESTING ALSO SHE LET ZERX HIT
BROOOO WHY LAFS ALWAYS SAYING SHE GOT BREAD BUT NO ONES SEEN ITTT
ONG MY NIGGA