L.C.L.Y. is actually, in chinese "lan si, lan yong", which means a big lousy show-off when he/she knows when he/she can't do something within his/her capability. This word is commonly used among asians or
chinese people when
gossiping.
It's also used to describe someones attitude whereby it also matches his/her face and
personality.
eg, there were two gals and her pals were
gossiping... that david ar, so damn L.C.L.Y.. He shows off his bicycle tricks and now look at him! he landed in
hospital already. It really matches his face and his
personality.