In a whisper is an expression used to describe speaking in a very quiet and low voice. The term can be broken down into two crossword solutions: FAINTLY (7 letters) and UNDERONESBREATH (15 letters). FAINTLY describes the volume of the speaking, while UNDERONESBREATH implies that the speaker is speaking quietly and privately. Together, these two solutions form the phrase 'in a whisper, ' which is used to describe speaking in a very quiet and low voice.