verb
-ens; -ened; -ening
[+ obj] :to make (something) bright, light, or clear
[no obj] :to become bright, light, or clear
verb
-ens; -ened; -ening
[+ obj] :to make (something) less heavy, difficult, or severe
[no obj] :to become less heavy, difficult, or severe
[+ obj] :to make (something) less sad or serious
[no obj] :to become less sad or serious
[no obj] :to become less forceful
lighten up
[phrasal verb] informal :to become more relaxed and informal :to stop being serious, worried, etc.