Lazy, after having left, that is, to be unoccupied (3,4)

'be unoccupied' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'lazy after having left that is' is the wordplay.
'lazy' becomes 'idle' (similar in meaning).
'after having' says to put letters next to each other.
'left' becomes 'l' (common abbreviation).
'that is' becomes 'ie' (abbreviation for id est, 'that is' in Latin).
'l'+'ie'='lie'
'idle' after 'lie' is 'LIE IDLE'.

'to' acts as a link.

Can you help me to learn more?