adj. 25B6; adjective
a knowledgeable old man : WELL INFORMED, learned, well read, (well) educated, erudite, scholarly, cultured, cultivated, enlightened.
he is knowledgeable about modern art : ACQUAINTED, familiar, conversant, au courant, au fait; having a knowledge of, up on, up to date with, abreast of; informal clued up, genned up; Brit. informal switched on.
ill-informed.