Formal clothing DJ initially wore (6)

I believe the answer is:

tuxedo

I'm a little stuck... Click here to teach me more about this clue!

'formal clothing' is the definition.
(I know that tuxedo is a type of formal clothing)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for tuxedo that I've seen before include "Dinner jacket (US)" , "An American monkey-suit" , "American dinner jacket" , "American DJ" , "Garment" .)

I've seen this clue in The Irish Times.

Want a hint initially instead of a full solution? Install my app