Sally at home with dog and boy around lunchtime? (9)
I believe the answer is:
incursion
'boy around lunchtime?' is the definition.
I can't tell whether this defines the answer.
'sally at home with dog' is the wordplay.
'sally' becomes 'sion' (I am not sure about this - if you are sure you should believe this answer much more).
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'home' becomes 'in' ('he's home' can mean 'he's in').
'with' is a charade indicator (letters next to each other).
'dog' becomes 'cur' (a cur is an aggressive or scruffy dog).
'in'+'cur'='incur'
'sion' after 'incur' is 'INCURSION'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for incursion that I've seen before include "Attack made into enemy territory" , "Hostile raid" , "Sudden attack" , "Foray" .)