Antonyms for communicative

informative:

uninformative, reticent, quiet, uncommunicative, reserved, unsociable, close-mouthed, unfriendly, silent.

noun:

close, blank, deadpan, expressionless, incommunicative, unutterable, inexpressive, vacuous, poker-faced, incommunicado, impassive, tightlipped, closemouthed, unpronounceable, unexpressive, mum, closelipped.

n.:

instrumental, mathematical, numerical, tight, unexpansive, unsigned.