Throw up (5)
I believe this is a double definition.
'throw' is the first definition.
(to lob something is to chuck or throw it)
'up?' is the second definition.
(thesaurus)
(Other definitions for lob that I've seen before include "Shot of Murray" , "Send in a high arc as in tennis or cricket" , "sky" , "Chuck" , "Throw ball in high arc" .)
'throw up' is the definition.
(heaving is a kind of throwing up)
This is all the clue.
(Other definitions for heave that I've seen before include "Retch - lift using much effort" , "Be sick; rise and fall" , "Big effort" , "Haul - retch" , "Gasp" .)
'throw up' is the definition.
(I know that throw up can be written as retch)
This is all the clue.
(Other definitions for retch that I've seen before include "Unsuccessful effort to vomit" , "Heave (as if to vomit)" , "Try to be sick" , "Strain throat as if vomiting" , "Try to vomit" .)