Poles suffer under slowcoach (5)
I believe the answer is:
snail
'slowcoach' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'poles suffer under' is the wordplay.
'poles' becomes 'SN' (North and South poles).
'suffer' becomes 'ail' (ailing is a kind of suffering).
'under' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'sn'+'ail'='SNAIL'
Can you help me to learn more?
(Other definitions for snail that I've seen before include "Slow mover" , "go very slowly" , "Slow-moving creature" , "Mollusc with coiled shell" , "Slow-moving garden pest" .)