Puñetero

complicated, difficult, spiteful, malicious, jerk

Within prefix origins ´´Puño´´, means ´´fist´´. The word has evolved with some imagination to refer to jerking off, with a fist motion of course. However, these words have lots of meanings depending on the context. Often it can be used as an adjective defining someone who complains alot or betrays you. Its use could be as simple as defining something as annoying.