形容詞 insecure:

1. not firm or firmly fixed; likely to fail or give way
2. lacking in security or safety
   同義詞：unsafe
3. lacking self-confidence or assurance
4. not safe from attack
   同義詞：unsafe

in.se.cure

adj.（形容詞）
Not sure or certain; doubtful:
不可靠的：不肯定的；懷疑的：
例句：
unemployed and facing an insecure future.
失業(yè)并面臨無保障的未來

Inadequately guarded or protected; unsafe:
無保障的：無足夠的守衛(wèi)或保護(hù)的；不安全的：
例句：
A shortage of military police made the air base insecure.
缺乏武警使得空軍基地不很安全

Not firm or fixed; unsteady:
不穩(wěn)固的，不牢固的：
例句：
an insecure foothold.
不穩(wěn)固的立足點

Lacking emotional stability; not well-adjusted:
不穩(wěn)定的：感情不穩(wěn)定的；沒有調(diào)整好的：
例句：
an insecure relationship.
不穩(wěn)定的關(guān)系

Lacking self-confidence; plagued by anxiety:
心神不定的：缺乏自信心的；為憂慮所擾的：
例句：
had always felt insecure at parties.
在晚會上總覺得心神不定

【引伸】
in.secure.ly
adv.（副詞）
in.secure.ness
n.（名詞）
in.secu.rity