Unpleasant way in possibly any case (5)
I believe the answer is:
nasty
'unpleasant' is the definition.
(nasty can mean unpleasant or horrible)
'way in possibly any case' is the wordplay.
I cannot quite understand how this works, but
'way' could be 'st' (abbreviation for street) and 'st' is found in the answer.
an anagram of 'any' is 'nay' which is located in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for nasty that I've seen before include "Offensive or malicious" , "Awful" , "Mean" , "Disagreeable" , "Vile" .)