In studies, returning leak gets trickier to plumb (7)
I believe the answer is:
deepens
'trickier to plumb' is the definition.
I can't judge whether this definition defines the answer.
'in studies returning leak' is the wordplay.
'in' indicates putting letters inside.
'studies' becomes 'dens' (I've seen this before).
'returning' shows that the letters should be reversed in order.
'leak' becomes 'pee' (I've seen this in another clue).
'pee' written backwards gives 'eep'.
'dens' placed around 'eep' is 'DEEPENS'.
'gets' acts as a link.
Can you help me to learn more?
(Other definitions for deepens that I've seen before include "Dredges" , "Intensifies" , "increases" , "gets stronger" , "Make further down, say ditch" .)