Heartless dame resides in Greek island and works as a programmer (5)
I believe the answer is:
codes
'works as a programmer' is the definition.
I can't judge whether this defines the answer.
'heartless dame resides in greek island' is the wordplay.
'heartless' says to hollow out the word (remove centre letters).
'resides in' means one lot of letters goes inside another.
'greek island' becomes 'cos' (Cos is a Greek island).
'dame' with its middle taken out is 'de'.
'de' placed into 'cos' is 'CODES'.
'and' is the link.
Can you help me to learn more?
(Other definitions for codes that I've seen before include "Word systems devised to create secrecy" , "System of letters etc for the purpose of secrecy" , "Sets of rules or cryptograms" , "Systems for transmitting secret messages" , "Ciphers" .)