Foot prints finally found by lake near the centre of Leek (7)
I believe the answer is:
spondee
'foot' is the definition.
(type of metrical foot in poetry)
'prints finally found by lake near the centre of leek' is the wordplay.
'finally' says to take the final letters.
'found by' means one lot of letters go next to another.
'lake' becomes 'pond' (pond is a kind of lake**).
'near the' is a charade indicator (letters next to each other).
'centre of' means to look at the middle letters.
The central letters of 'leek' are 'ee'.
The final letter of 'prints' is 's'.
's'+'pond'+'ee'='SPONDEE'
(Other definitions for spondee that I've seen before include "No speed required for poetic metrical foot" , "bit of verse" , "Metric foot of two long syllables" .)