Redneck regularly gets swimmer to overstep the mark (8)
I believe the answer is:
encroach
'overstep the mark' is the definition.
'encroach' can be an answer for 'overstep' (thesaurus). I'm not sure about the 'the mark' bit.
'redneck regularly gets swimmer' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'gets' means one lot of letters go next to another.
'swimmer' becomes 'roach' (roach is a type of fish).
The alternate letters of 'redneck' are 'enc'.
'enc'+'roach'='ENCROACH'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for encroach that I've seen before include "Tread on someone's toes" , "Invade" , "Gradually intrude (on person's area)" , "Intrude on someone's territory or time" , "Advance gradually (beyond expected limits)" .)