lighten up

present singular third person lightens up · participle present lightening up · participle past lightened up · past lightened up

1. idiomaticintransitivetransitiveTo make (something) or to become less serious and more cheerful or casual; to relax.

   I wish he'd lighten up a bit and realize that we were only joking.

   3 more examples

   The mood at work has been tense, so he's looking for ways to lighten it up.

   Sondheim's sense of life — which is pretty pessimistic (I don't think that anyone ever ends happily ever after in a Sondheim musical) — is brought through without trying to lighten it up.

   1983 August 6, Michael Bronski, “Gay Sensibility, Straight Imitation”, in Gay Community News, page 8

   you lighten up my heart when I start to cry

   2008, Adele, First Love

2. transitiveTo lighten (something): to decrease its weight.

   Near-synonym: slim down

   1 more example

   He can't get any more power out of it [his drag racer], so now he's looking for ways to lighten it up.

   Synonyms: slim down