From WikiFur, the furry encyclopedia.
A chuff (to chuff, chuffing) is the sound made by large cat species such as tigers, or from whales and dolphins. For feline species, it used as a greeting to family members or companions, and denotes happiness, similar to a house cat's purr. The sound can be described as a stuttering cough.
For dolphins and whales, a chuff is usually a fast exhale done for equivalent reasons to a human sneeze or cough, but can also be done as a sign of exasperation, aggression, or frustration.