'yes-man' originates from Modern English, formed from the words 'yes' + 'man', where 'yes' meant 'an affirmative response' and 'man' meant 'person'.

'yes-man' emerged in early 20th-century American English as a compound describing a person who always says 'yes' to superiors; the term gained currency in political and business contexts by the 1920s–1930s and has retained a generally pejorative sense.

Initially it simply described 'a person who says yes'; over time it acquired a stronger negative sense of 'a sycophant' or someone who agrees uncritically to gain advantage.