1. rude slang To meddle with, interfere with, or tweak something, often in an uncareful or casual way. Please stop fucking with the thermostat. I try to avoid the temptation to fuck with a recipe the first time I make it, but I usually end up at least adding some seasoning.

2. rude slang To antagonize or threaten someone. If you keep fucking with Derrick, he's going to snap. Fuck with me again and see what happens.

3. rude slang To tease or attempt to deceive someone, typically as part of a prank or practical joke. Come on, don't fuck with me. Did Tina really ask about me?

4. rude slang To involve oneself with a risky thing or situation. Nah, man, I do not fuck with cocaine. What are you doing fucking with that crew? You're going to get into some messed up shit.