Cockney’s tresses initially blonde, then silver after effect of car crash (6)
I believe the answer is:
airbag
'effect of car crash' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'cockney's tresses initially blonde then silver' is the wordplay.
'cockney's tresses' becomes ''air' ('hair' - I've seen this in another clue - said with the 'H' dropped - a cockney accent.).
'initially' suggests taking the first letters.
'then' says to put letters next to each other.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
The initial letter of 'blonde' is 'b'.
'air'+'b'+'ag'='AIRBAG'
'after' is the link.
Can you help me to learn more?
(Other definitions for airbag that I've seen before include "that's deployed to save a life" , "Protection" , "cushion" , "thing rarely subject to inflation" , "safety feature" .)