titter nervously 紧张地窃笑
titter at someone 对某人窃笑
break into a titter 突然轻笑
stifle a titter 忍住笑声
nervous titter 紧张的窃笑
A: Why are you tittering during class?
A：你为什么在课堂上窃笑？
B: I couldn't help it, the situation was funny.
B：我忍不住，那情况太好笑了。
1) 因尴尬或紧张发出的轻声笑
2) 在不适当场合压低的笑声
3) 表示害羞或不好意思的笑
1. 轻声窃笑；咯咯笑
2. （名词）窃笑声
verb
1. To laugh quietly and nervously, especially in a way that shows embarrassment or amusement.
Synonym: giggle, snicker