It may take an age to get a suntan (6)
I believe the answer is:
bronze
'suntan' is the definition.
(thesaurus)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for bronze that I've seen before include "Third-place medal" , "Hard alloy suitable for casting" , "Third prize" , "Copper and tin alloy - sculpture" , "Tan; metal alloy" .)