It's apt to arise on the south side (5)
I believe the answer is:
steam
'it's apt to arise' is the definition.
I can't tell whether this definition defines the answer.
'on the south side' is the wordplay.
'on' is a charade indicator (letters next to each other).
'the south' becomes 's' (abbreviation).
'side' becomes 'team' (a side is a sporting team).
's'+'team' is 'STEAM'.
Can you help me to learn more?
(Other definitions for steam that I've seen before include "letter opener?" , "A lot of hot air" , "Energy (colloq.)" , "Gas from boiliing water" , "Like old radio" .)