taciturnity, reserve, reticense, reticency, irreticence, tight-lippedness, tightlippedness, diffidence, inaffability, reservedness, more...

outspokenness, candor, frankness, openness

such, natural, certain, own, extreme, usual, very, initial, general, habitual, much

not answering,   quiet nature,   reserved attitude,   reluctance to speak,   needless reserve,   hesitation to speak,   tight lip,   reserved feelings