to become lighter or less dark; brighten

The sky lightened after the storm.

to brighten or light up, as the eyes or features

Her face lightened when she heard the good news.

to flash as or like lightning (often used impersonally with it as subject)

It thundered and lightened for hours.

Archaic . to shine, gleam, or be bright

steel blades lightening in the sun.

to give light to; illuminate

A full moon lightened the road.

to brighten (the eyes, features, etc.)

A large smile lightened his face.

to make lighter or less dark

Add white to lighten the paint.

Obsolete . enlighten.

Obsolete . to flash or emit like lightning (usually fol. by out, forth, or down )

eyes that lightened forth implacable hatred.

verb

blacken , darken , dim , dull , burden , weigh down , bring down , depress , upset

verb

become light , brighten , flash , gleam , illume , irradiate , light , light up , make bright , shine , allay , alleviate , ameliorate , assuage , attenuate , buoy , change , comfort , cut down , decrease , dilute , disburden , disencumber , ease , empty , eradicate , extenuate , facilitate , free , jettison , lessen , levitate , make less , make lighter , mitigate , mollify , pour out , put off , reduce , relieve , remove , shift , take , take a load off , thin , throw out , unburden , unload , uplight , upraise , buoy up , cheer , elate , encourage , gladden , hearten , lift , perk up , revive , illumine , palliate , bleach , fade , illuminate , trim