Feel bad securing dry nick (6)
I believe the answer is:
fettle
'nick' is the definition.
(both can mean health or condition)
'feel bad securing dry' is the wordplay.
'bad' indicates anagramming the letters.
'securing' indicates putting letters inside.
'dry' becomes 'tt' (abbreviation for teetotal).
'feel' anagrammed gives 'fele'.
'fele' enclosing 'tt' is 'FETTLE'.
(Other definitions for fettle that I've seen before include "Condition, trim - best when fine" , "Be in fine . . . . . . to be in excellent form" , "A state of fitness and good health" , "Condition or trim, often fine" , "Condition, trim - sometimes fine" .)