Fall back, anyhow, slap into the middle of the green (7)
I believe the answer is:
relapse
'fall back' is the definition.
('relapse' can be a synonym of 'fall back')
'anyhow slap into the middle of the green' is the wordplay.
'anyhow' indicates anagramming the letters.
'into' means one lot of letters goes inside another.
'the middle of' means to look at the middle letters.
The middle of 'green' is 'ree'.
'slap' with letters rearranged gives 'laps'.
'laps' put into 'ree' is 'RELAPSE'.
(Other definitions for relapse that I've seen before include "Fall back into former condition, being pleaser" , "Fall back like leapers" , "Fall back (into ill health)" , "Become sick again" , "Downturn in health (after improvement)" .)