Arctic plan almost could be workable (9)
I believe the answer is:
practical
'workable' is the definition.
(thesaurus)
'arctic plan almost could be' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'could be' is an anagram indicator.
'arctic'+'plan'='arcticplan'
'arcticplan' with its final letter taken away is 'arcticpla'.
'arcticpla' is an anagram of 'PRACTICAL'.
(Other definitions for practical that I've seen before include "Effective; virtual" , "Down-to-earth" , "type of examination" , "Functional, pragmatic" , "Pragmatic, hard-nosed" .)