uneasy, anxious, or unsure; feeling unsettled because the outcome is uncertain.
試験の合否が出ていなくて心もとない。
I'm uneasy because the exam results haven't come out yet.
夜道を一人で歩くのは心もとない。
Walking alone on the road at night feels unsettling.
約束が曖昧で、頼りなくて心もとない。
The promise was vague and unreliable, so I feel uneasy.
unreliable, untrustworthy, or undependable; used for people or things that can't be relied upon.
この古いエレベーターはいつ止まるかわからず心もとない。
This old elevator is unreliable; you never know when it will stop.
彼の約束の守り方が心もとないので、任せられない。
His habit of not keeping promises is unreliable, so I can't entrust him.
連絡が途絶えがちで心もとない状況だ。
It's an unsettling situation because communications tend to be cut off.
archaic: nervous or impatient from anxiety; restless due to worry (old-fashioned usage).
出征の日、家族は心もとなくて涙を浮かべた（古風な表現）。
On the day of departure for battle, the family was anxious and tearful (archaic expression).
archaic: unclear or indistinct; vague, as if something is unsettled or not clearly perceived.
霧のため景色が心もとなく見えた（古語的表現）。
The scenery looked indistinct because of the fog (archaic usage).