means A reluctance to speak freely — the habit of holding back one's thoughts, feelings, or words, especially when others would gladly spill them.

from From Latin reticere, "to keep silent," built from re- (an intensifier) plus tacere, "to be quiet" — the same hush at the root of tacit and taciturn. It entered English in the 17th century, carrying with it the sense not of mere silence but of silence deliberately maintained, a quiet held on purpose.