Weird like retreating top-class warriors (7)
I believe the answer is:
samurai
'warriors' is the definition.
(I've seen this before)
'weird like retreating top-class' is the wordplay.
'weird' becomes 'rum' (rum can mean strange).
'like' becomes 'as'.
'retreating' shows that the letters should be reversed in order.
'top class' becomes 'AI' (resembles A1, old-fashioned term meaning excellent).
'rum'+'as'='rumas'
'rumas' written backwards gives 'samur'.
'samur'+'ai'='SAMURAI'
(Other definitions for samurai that I've seen before include "Traditional Japanese warriors" , "Sudoku variant" , "Member of military class" , "Feudal Japanese warrior" , "Former Japanese military caste member" .)