Motel life holds up 27 (6)
I believe the answer is:
fillet
'27' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'motel life holds up' is the wordplay.
'holds' indicates the answer is hidden within the clue.
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'tellif' is hidden within 'motel life'.
'tellif' backwards is 'FILLET'.
Can you help me to learn more?
(Other definitions for fillet that I've seen before include "Alice band" , "Piece of tender boneless meat" , "Remove certain content" , "Remove bone from (meat or fish)" , "Choice piece of boneless meat (6)" .)