All there by about ten to one again (6)
I believe the answer is:
entire
'all' is the definition.
(I've seen this in another clue)
'about ten to one again' is the wordplay.
'about' is an anagram indicator.
'to one' becomes 'i' (Roman numeral).
'again' becomes 're' (prefix meaning 'again').
'ten' is an anagram of 'ent'.
'ent'+'i'+'re'='ENTIRE'
'there by' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for entire that I've seen before include "Envelope" , "outright" , "Unmitigated" , "porter" , "Full, intact" .)