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English definition of “lighten up”

lighten up

informal
verb uk phrasal verb with lighten   /ˈlaɪ.tən/ us    /-t̬ən/
to become more relaxed and less serious: Oh, lighten up! I was only joking! I wish she'd lighten up a bit.Calming and relaxing
(Definition of lighten up from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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