Synonyms for Incommunicative (same or very similar meaning)
WordNet sense 1 (failing to speak or communicate etc when expected to):
silentWordNet sense 2 (inclined to secrecy or reticence about divulging information):
closeWordNet sense 3 (not inclined to talk or give information or express opinions):
uncommunicativeFrom the ODE community, based on WordNetadd/edit