1) Evasive 2) Guarded 3) Incommunicative 4) Uncommunicative 5) Unrevealing 1) Guarded 2) Incommunicative 3) Uncommunicative 4) Unrevealing 
• (n.) A state of not being committed or pledged; forbearance or refusal to commit one`s self. Also used adjectively. • (n.) A state of not being committed or pledged; forbearance or refusal to commit one`s self. Also used adjectively.
Non`com·mit'tal noun A state of not being committed or pledged; forbearance or refusal to commit one's self. Also used adjectively. 
adjective refusing to bind oneself to a particular course of action or view or the like; `her boyfriend was noncommittal about their future together`
not committing oneself, or not involving committal, to a particular view, course, or the like: The senator gave us a noncommittal answer.
[SAT terms] refusing to bind oneself to a particular course of action