"rasping" means "to have trouble breathing, to breathe noisily. Someone who is soon to die may begin rasping as it gets more difficult for them to breathe.
I can think of no single common English word that would mean "to breathe perfectly/ healthily"
exit
Provoke.
sooth
The sound of the rake rasping against the pavement filled the garden.
Chronic bronchitis can lead to a rasping cough that is difficult to cure.
Participant and Player.
very surprised
Yes, "rasping" is an onomatopoeic word because it mimics the sound it describes. The word itself gives a similar impression to the harsh, grating sound of rasping.
Antonym means the opposite.
roared, premature, early
the antoynm of forage is "distribute"
An antonym for investigate is ignore.