self-restrained

aloof backward bashful cautious ceremonious close close-mouthed cold collected composed controlled conventional cool demure diffident distant eremitic formal frigid gentle icy inhibited mild misanthropic modest noncommittal offish peaceful placid prim quiet reclusive restrained reticent retiring secretive sedate self-contained self-controlled serene shy soft-spoken solitary standoffish taciturn unapproachable uncommunicative uncompanionable undemonstrative unresponsive withdrawn