Continually (5,3,3)
(Other definitions for night and day that I've seen before include "twenty-four hours in length?" , "24 - 7" , "Cole Porter music" , "Play" , "All the time (Sinatra song)" .)
'continually' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for forever that I've seen before include "as diamonds are" , "continually" , "till Doomsday" , "permanently" , "Till hell freezes over" .)
'continually' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for on and on that I've seen before include "continuously" , "At tedious length" , "Endlessly" , "Continuing or continually" , "Ever" .)
'continually' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for always that I've seen before include "Every time" , "Eternally" , "Evermore" , "For ever" , "Perpetually" .)