1. rude slang To engage in aimless recreation or frivolous time-wasting; to fool around. I can't believe we spent the whole day just fucking around online.

2. rude slang To deceive someone. In this usage, a noun or pronoun can be used between "fuck" and "around." Come on, don't fuck me around. Is this a serious offer or not?

3. rude slang To tease or play a prank on one, often by trying to get them to believe something that is not true. Please stop fucking around. You didn't really hear a knock on the window, did you? Did she really ask you about me, or are you fucking around with me?

4. rude slang To joke about something. Often used in the negative to indicate absolute seriousness. Oh, come on, Tina, we're just fucking around. We didn't mean it. You guys, Mom is not fucking around. She said she would ground us for a month if she caught us again.

5. vulgar slang To be promiscuous. Well, I wouldn't trust Phil if I were dating him—I hear he fucks around.