形容詞 diffident:

1. showing modest reserve
2. lacking self-confidence
   同義詞：shy, timid, unsure

1. He is diffident about expressing his opinions.
   他對于表達自己的意見感到膽怯。
2. The quality or state of being diffident; timidity or shyness.
   缺乏自信; 膽怯缺乏自信的性質(zhì)或狀態(tài); 膽小的或羞怯的

dif.fi.dent

adj.（形容詞）
Lacking or marked by a lack of self-confidence; shy and timid.See Synonyms at shy
缺乏自信的；羞怯的和膽小的參見 shy
Reserved in manner.
躊躇的：方式上采取保留的態(tài)度

來源：
Middle English
中古英語
from Latin diffodôns diffodent- [present participle of] diffodere [to mistrust]
源自 拉丁語 diffodôns diffodent- [] diffodere的現(xiàn)在分詞 [不信任]
dis- [dis-]
dis- [前綴，表相反的意思]
fodere [to trust] * see bheidh-
fodere [相信] *參見 bheidh-

【引伸】
dif.fidently
adv.（副詞）