Puerto Rican slang (and also used in some other Caribbean islands). Usually, it means to be head over heels in love. It can also be used as to describe someone who is very excited about something. In Mexico and Central America, it means to be very pleased about something.
(culeco is masculine, culeca is feminine)

1. noun. It is the sudden feeling of an inexplicable joy one gets when something romantic or idealistic occurs.

When kilig, one may experience the following:

*butterflies in one's stomach
*heart melting
*shivers down one's spine
*irrepressible noises from one's mouth
*uncontrollable smiling
*an inner conflict between hope of something wished for and reality

Kilig may also be defined as that mountain top, floating, on cloud nine, invincible, i-could-keep-smiling, heart aching goodness and feeling which overpowers the mind's ability to think straight, act straight, breathe properly and articulate thoughts into a single comprehensible sentence.

A fat ass