To take upon oneself: assume responsibility; assume another's debts. To undertake the duties of (an office): assumed the presidency. To take on; adopt: "The god assumes a human form\u201d ( John Ruskin). To put on; don: The queen assumed a velvet robe. To affect the appearance or possession of; feign. To take for granted; suppose: assumed that prices would rise. See Synonyms at presume. To take over without justification; seize: assume control. To take up or receive into heaven.