Why an operation at first is botched carelessly (6)
I believe the answer is:
anyhow
'carelessly' is the definition.
(thesaurus)
'why an operation at first is botched' is the wordplay.
'at first' indicates taking the first letters.
'is botched' indicates anagramming the letters.
The first letter of 'operation' is 'o'.
'why'+'an'+'o'='whyano'
'whyano' with letters rearranged gives 'ANYHOW'.
(Other definitions for anyhow that I've seen before include "In whatever way" , "One way or another" , "Randomly - at least" , "In a muddle" , "in a mess" .)