Stealing article on foot (5)
I believe the answer is:
theft
'stealing' is the definition.
(I know that stealing can be written as theft)
'article on foot' is the wordplay.
'article' becomes 'the' (the definite article).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'foot' becomes 'ft' (abbreviation).
'the'+'ft'='THEFT'
(Other definitions for theft that I've seen before include "Act of larceny" , "A 19" , "Pilfering" , "Dishonest appropriation" , "Taking offence?" .)