Contrition concerning dots and dashes (7)
I believe the answer is:
remorse
'contrition' is the definition.
(I've seen this before)
'concerning dots and dashes' is the wordplay.
'concerning' becomes 're' (both can mean on a particular topic).
'dots and dashes' becomes 'morse' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
're'+'morse'='REMORSE'
Can you help me to learn more?
(Other definitions for remorse that I've seen before include "Penitence" , "Distress from a sense of guilt" , "Sorrow for wrong committed" , "Pity" , "Ruefulness" .)