Tips second half over the sewage (7)
I believe the answer is:
cesspit
'sewage' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'tips second half over' is the wordplay.
'half' suggests halving the letters.
'over' is a reversal indicator.
'second' halved is 'sec'.
'tips'+'sec'='tipssec'
'tipssec' in reverse letter order is 'CESSPIT'.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for cesspit that I've seen before include "Sump" , "Foul and squalid place" , "means of waste disposal" , "Sewage receptacle" , "Place for filthy water" .)