Slip back on circuit slowly beginning here at the end (7)
I believe the answer is:
relapse
'slip back' is the definition.
(I've seen this before)
'on circuit slowly beginning here at the end' is the wordplay.
'on' becomes 're' (regarding).
'circuit' becomes 'lap' (synonyms).
'slowly beginning here' becomes 'se' (I can't explain this - if you can you should give a lot more credence to this answer).
'at the end' means one lot of letters go next to another.
're'+'lap'+'se'='RELAPSE'
Can you help me to learn more?
(Other definitions for relapse that I've seen before include "Take a turn for the worse" , "Fall back (into ill health)" , "A return to illness" , "Slide back into former condition as of illness (7)" , "causing setback to recovery" .)