Welche Bedeutung steckt hinter der hier vorgestellten Vokabel aus dem Bereich Colleague to colleague?

Zane: 'I'm disappointed that my suggestion didn't get more acceptance from Jan.' Peter: 'Oh don't worry about it. I think it's just a case of sour grapes because she didn't get promoted at the same time as you.'

sour grapes

Do you know what it means?

• a bad mood which arises from feeling unwell
• behaving badly after being rejected
• a bad habit