Breathe like this: "Harrr" (8)
I believe the answer is:
aspirate
'breathe' is the definition.
(thesaurus)
'like this harrr' is the wordplay.
'like' becomes 'as'.
'this harrr' becomes 'pirate' (I am not sure about this - if you are sure you should believe this answer much more).
'as'+'pirate'='ASPIRATE'
Can you help me to learn more?
(Other definitions for aspirate that I've seen before include "Pronounce the letter H at the beginning of a word" , "challenge to Eliza" , "Pronounce with full breathing" , "Pronounce with an h, like parasite" , "H sound - suck air in or out" .)