Lighten up and Let go

Lighten up verb - Make lighter or brighter.

Let go and lighten up are semantically related in let up topic. In some cases you can use "Let go" instead a verb "Lighten up".

Let go verb - Release, as from one's grip.

Lighten up and let go are semantically related in let up topic. You can use "Lighten up" instead a verb phrase "Let go".