a. 未得保证的, 无把握的, 不安全的, 未保险的

[ adj ]
lacking boldness or confidence
<adj.all>

Unassured \Un`as*sured"\, a.
1. Not assured; not bold or confident.

2. Not to be trusted. [Obs.] --Spenser.

3. Not insured against loss; as, unassured goods.