Do you briefly join a western den of insurance workers? (9)
I believe the answer is:
actuarial
'do you briefly join' is the definition.
I can't tell whether this defines the answer.
'a western den of insurance workers?' is the wordplay.
I cannot really see how this works, but
'a' is within the answer.
'workers?' could be 'tu' (abbreviation for trade union) and 'tu' is found in the answer.
'insurance' could be 'car' (car insurance is a kind of insurance) and 'car' is found in the leftover letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for actuarial that I've seen before include "risky business" , "Dealing with business figures" , "Calculating risks" , "Relating to insurance calculations" , "Of the work of statisticians who calculate insurance premiums" .)