Drool when rising tardily about four (8)
I believe the answer is:
salivate
'drool' is the definition.
(thesaurus)
'when rising tardily about four' is the wordplay.
'when' becomes 'as'.
'rising' is a reversal indicator (going up in a down clue).
'tardily' becomes 'late' ('late' can be a synonym of 'tardily').
'about' means one lot of letters goes inside another.
'four' becomes 'iv' (roman numeral).
'as' reversed gives 'sa'.
'late' enclosing 'iv' is 'livate'.
'sa'+'livate'='SALIVATE'
(Other definitions for salivate that I've seen before include "Drool" , "Water at the mouth" , "Make mouth moisture in aestival manner" , "Produce moisture in mouth" , "Lisa a vet (anag.)" .)