"tittering" in the verb sense
1. giggle, titter
laugh nervously
"The girls giggled when the rock star came into the classroom"
"tittering" in the adjective sense
1. thoriated, tittering
being or sounding of nervous or suppressed laughter
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License