Untidy writing goes from speedy start to go-slow (6)
I believe the answer is:
scrawl
'untidy writing' is the definition.
(I've seen this before)
'speedy start to go-slow' is the wordplay.
'start to' suggests taking the first letters.
'go slow' becomes 'crawl' (I've seen this before).
The initial letter of 'speedy' is 's'.
's'+'crawl'='SCRAWL'
'goes from' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for scrawl that I've seen before include "Write carelessly or badly" , "write hurriedly" , "Hasty writing" , "Write untidily" , "Poor handwriting" .)