Ladilla is the spanish word for crab louse. Therefore it's usually used to reflect that someone can be as annoying as a crab louse. It can also be use in the form of a verb "ladillar". For it's sexually related content, it can also be found in expressions with such intention.
"Hombre, eres una ladilla" as in "Boy, you are such a pain", or "deja de ladillar" as in "Quit fooling around".
by Willy en Baires April 05, 2006
It's a word most used by the Venezuelan people, to refer of someone or something as annoying
Tu eres una ladilla!!! You are very annoying..
by Leonardo Goncalves December 14, 2007