tit·ter 
/ˈtɪtɚ/ verb
tit·ters; tit·tered; tit·ter·ing /ˈtɪtɚ/ verb [no obj] : to laugh in a quiet and nervous way
▪ Some people in the audience tittered nervously during an awkward pause in the speech.
▪ Some people in the audience tittered nervously during an awkward pause in the speech.
— titter noun, plural titters [count]
▪ There were a few titters in the classroom.
▪ There were a few titters in the classroom.
