Letter a deadhead may be late with (5)
I believe the answer is:
delta
'letter a deadhead' is the definition.
'delta' can be an answer for 'letter' (Greek letter). I am not certain of the 'a deadhead' bit.
'late with' is the wordplay.
I cannot quite see how this works, but
an anagram of 'late' is 'elta' which is present in the answer.
A single letter 'd' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'may be' is the link.
Can you help me to learn more?
(Other definitions for delta that I've seen before include "Eg, outlet of the Nile" , "Fragmented estuary" , "Nile river mouth" , "Alluvial area - Greek letter" , "Daedalus started with this" .)