Steal heartless earl’s cash abroad (6)
I believe the answer is:
nickel
'cash abroad' is the definition.
(five cent coin in the US)
'steal heartless earl's' is the wordplay.
'steal' becomes 'nick' (nick can informally mean to steal).
'heartless' says to hollow out the word (remove centre letters).
'earl' with its centre removed is 'el'.
'nick'+'el'='NICKEL'
(Other definitions for nickel that I've seen before include "A 5-cent coin in USA" , "Metallic element, Ni" , "Sliver of wood/glass" , "American 5-cent piece" , "Metal; five US cents" .)