señor

mister, sir, lord (title conferred on a married or older male); gentleman; master

“Señor, cierre la puerta.” — Sir, close the door.

Inherited from Old Spanish sennor (“lord”), from Vulgar Latin *senjor (“master, elder, lord, nobleman”), from Latin seniōrem (“elder”), comparative form of senex (“old”). Doublet of sénior, borrowed from Latin.

great big; whopping; free

“dale un señor golpe” — give him a good big whack

From señor in the sense of mister, a title which gives importance to men and signals their social status; from there it was applied to masculine nouns in order to achieve a similar effect with them. Compare Portuguese senhor (adjective).