Shyness

Shyness is the quality of being quiet and self-conscious due to feelings of inadequacy.

Some synonyms are:

afraid, apprehensive, averse, backward, bashful, cautious, chary, circumspect, conscious, coy, demure, diffident, disinclined, distrustful, fearful, hesitant, humble, indisposed, introverted, loath, loner, modest, nervous, recessive, reluctant, reserved, reticent, retiring, self-effacing, shamefaced, sheepish, shrinking, skittish, suspicious, timid, unassertive, unassured, uneager, uneffusive, unresponsive, unsocial, unwilling, wary