Pitch in triplets regularly ignored (4)
I believe the answer is:
tilt
'pitch' is the definition.
(I know that pitch can be written as tilt)
'triplets regularly ignored' is the wordplay.
'regularly ignored' means one should take alternating letters (letters removed at regular intervals).
The alternating letters of 'triplets' are 'TILT'.
'in' acts as a link.
(Other definitions for tilt that I've seen before include "Slope; use a lance in jousting" , "Lean sideways" , "Lean, slope" , "Cause to slope or incline" , "Inclination, joust" .)