a bit on the side

1. A person who is involved in a sexual relationship with someone who is married. Primarily heard in UK, Australia. I spotted Harry at the diner with a woman much younger than his wife. She must be his bit on the side. She's been with her husband for 30 years, so it was a shock to everyone when we found out she had a bit on the side. I know my ex always had a bit on the side because he was so shady about it.

2. Such a relationship. I spotted Harry at the diner with a woman much younger than his wife. I think he's having a bit on the side. I'm happily married, so I have no need for a bit on the side. Are you serious? You've only been married six months and you have a bit on the side?

3. Income from an additional job. My wife has started to earn a bit on the side to help us offset all the extra expenses from the renovation. I get a bit on the side by cleaning houses. It’s not a ton of money, but it does help. I used to make a bit on the side, but I no longer have to, thanks to this pay increase at my 9-5 job.

bit on the side

1 a person with whom you are unfaithful to your partner. 2 a relationship involving being unfaithful to your partner. 3 money earned outside your normal job. informal