opacate

/ˈəʊpəkeɪt/

Etymology

Borrowed from Latin opācātus, perfect passive participle of opācō, see -ate (verb-forming suffix).

verb

  1. To darken; to cloud.“[…] when the same corpuscles, upon the unstopping of the glass, were put into a new motion, and disposed after a new manner, they did opacate that part of the air they moved in.”