Insecure, a.
1. Not secure; not confident of safety or permanence; distrustful; suspicious; apprehensive of danger or loss. With sorrow and insecure apprehensions. Jer. Taylor.
2. Not effectually guarded, protected, or sustained; unsafe; unstable; exposed to danger or loss. Bp. Hurg. The trade with Egypt was exceedingly insecure and precarious. Mickle.
Shades of meaning
Fernald has no entry of its own for insecure; he lists it under precarious.
He lists it without comment; the entries above explain its neighbors.