Meaning

verb cause to be calm or quiet as by administering a sedative to

adjective characterized by dignity and propriety

adjective dignified and somber in manner or character and committed to keeping promises

originThe adjective is derived from Late Middle English sedate (“not painful or sore”), and directly from its etymon Latin sēdātus (“calm, quiet, composed”), participial adjective from sēdō (“to allay, appease, calm, settle; to end, stop”), ultimately from Proto-Indo-European *sed- (“to sit”). Compare English -ate (suffix forming adjectives meaning ‘characterized by [the thing specified]’). The verb is…

Etymology from Wiktionary, CC BY-SA 3.0