Having recovered from, once again (4)
I believe the answer is:
over
'once again' is the definition.
(thesaurus)
'having recovered from' is the wordplay.
'from' says the answer is hidden in the clue.
'OVER' is hidden within 'having recovered'.
(Other definitions for over that I've seen before include "jumped fence" , "Finished; six balls" , "Finished like cricket period" , "Higher than; finished" , "Round of six bowls in cricket - then it's finished" .)