to take in (something, such as water) in a natural or gradual way. to take in (knowledge, attitudes, etc.): ACQUIRE, LEARN. USE UP, CONSUME. to take in and make part of an existent whole. to engage or engross wholly. to receive without recoil or echo. ENDURE, SUSTAIN. ASSUME, BEAR. to transform (radiant energy) into a different form especially with a resulting rise in temperature.