dark·en 
/ˈdɑɚkən/ verb
dark·ens; dark·ened; dark·en·ing /ˈdɑɚkən/ verb 1 : to make (something) dark or to become dark or darker in color [+ obj] ▪ Clouds darkened the sky. ▪ The hours I spent in the sun darkened [=tanned] my skin. [no obj] ▪ The sky darkened and it started to rain. ▪ Her face darkens to a deep red when she gets angry. ▪ The wood will darken as it ages. 2 : to make (something) less happy or to become less happy [+ obj] ▪ The bad news darkened his mood. ▪ The last days of her life were darkened by illness. [no obj] ▪ His mood darkened after he heard the bad news.
darken someone's door/doors
: to go to or appear at a place where you are not welcome anymore
▪ She told him to leave and to never darken her door again. [=to never go to her house/apartment again]
▪ She told him to leave and to never darken her door again. [=to never go to her house/apartment again]
— darkened adjective
▪ He was sitting in a darkened [=dark] corner of the room. ▪ a car with darkened [=dark] windows
▪ He was sitting in a darkened [=dark] corner of the room. ▪ a car with darkened [=dark] windows
