Holiday on the outskirts of Naples gives them a lift (7)

'them a lift' is the definition.
I can't tell whether this definition defines the answer.

'holiday on the outskirts of naples' is the wordplay.
'holiday' becomes 'leave' (I've seen this before).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'the outskirts of' means to remove the middle letters (only letters on the outskirts).
'naples' with its middle removed is 'ns'.
'leave'+'ns'='LEAVENS'

'gives' is the link.

Can you help me to learn more?