At four, Conservative loses the head, going almost white (5)
I believe the answer is:
ivory
'white' is the definition.
(I know that ivory is a type of white)
'at four conservative loses the' is the wordplay.
'at' means one lot of letters go next to another.
'four' becomes 'IV' (Roman numerals).
'conservative' becomes 'tory' (Tory means a member of the Conservative Party).
'loses' indicates named letters should be taken away.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'tory' with 't' taken out is 'ory'.
'iv' next to 'ory' is 'IVORY'.
'head going almost' is the 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 ivory that I've seen before include "National emblem" , "Shade of white" , "Piano-key" , "Substance in elephant tusks" , "Smooth material of elephant tusks" .)