Early doter on man was spotty (6)
I believe the answer is:
dotted
'spotty' is the definition.
(thesaurus)
'early doter on man' is the wordplay.
'early doter' becomes 'dot' (I can't justify this - if you can you should give a lot more credence to this answer).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'man' becomes 'ted' (Ted is a man's name).
'dot'+'ted'='DOTTED'
'was' acts as a link.
Can you help me to learn more?
(Other definitions for dotted that I've seen before include "Sign on this line to authorise" , "Marked with small spots" , "I may be" , "Having a pattern of small round marks" , "Covered with spots" .)