umbra n.

early 15c., "shadow, darkness, shade," from Old French ombrage "shade, shadow," from noun use of Latin umbraticum "of or pertaining to shade; being in retirement," neuter of umbraticus "of or pertaining to shade," from umbra "shade, shadow," from PIE root *andho- "blind; dark" (source also of Sanskrit andha-, Avestan anda- "blind, dark").

The English word had many figurative uses in 17c.; the one remaining, "suspicion that one has been slighted," is recorded by 1610s; hence phrase to take umbrage at, attested from 1670s. Perhaps the sense notion is similar to whatever inspired the modern (by 2013) slang verbal phrase throw shade "(subtly) insult (something or someone)."