Shortest cigarette end that will last out? (5)
I believe the answer is:
least
'shortest' is the definition.
(thesaurus)
'cigarette end that will last out?' is the wordplay.
'end' indicates one should take the final letters.
'that will' is a charade indicator (letters next to each other) (I've seen this in other clues).
'out?' is an anagram indicator (I've seen 'out of' mean this).
The last letter of 'cigarette' is 'e'.
'e'+'last'='elast'
'elast' is an anagram of 'LEAST'.
(Other definitions for least that I've seen before include "Smallest in amount or degree" , "To the lowest degree" , "Superlative form of 'little'" , "Bottom" , "Most slight" .)