Слово "insecurity". Англо-русский словарь Мюллера

“May it be right then,” I said, as I rose, deeming it useless to continue a discourse which was all darkness to me; and, besides, sensible that the character of my interlocutor was beyond my penetration; at least, beyond its present reach; and feeling the uncertainty, the vague sense of insecurity, which accompanies a conviction of ignorance.

Can I tell the person I love the most my deepest insecurities?

Michael manifests the consuming insecurity of a skin condition

Proud and vainglorious to the point of insecurity, of hypochondria; seeking all those two months for at least some point on which he could rest with a certain dignity and show himself nobly; feeling himself still a novice on the chosen path, who might fail to keep to it; finally, in despair, having resolved to become totally insolent in his own house, where he was a despot, but not daring to show the same resolve before Nastasya Filippovna, who went on confusing him until the last moment and mercilessly kept the upper hand; "an impatient pauper," in Nastasya Filippovna's own phrase, of which he had been informed; having sworn with all possible oaths to exact painful recompense for it later, and at the same time occasionally dreaming childishly to himself of making all ends meet and reconciling all opposites—he now had to drink this terrible cup as well and, above all, at such a moment!

It struck him that the truly characteristic thing about modern life was not its cruelty and insecurity, but simply its bareness, its dinginess, its listlessness.