Inconsiderate thing for Billingsgate trader to do, it’s said (7)

I believe the answer is:

selfish

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

'inconsiderate' is the definition.
('selfish' is associated in meaning with 'inconsiderate')

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for selfish that I've seen before include "Concerned only with one's personal welfare" , "for personal gain" , "Concerned only with no. 1" , "Putting own interests first" , "Egocentric - greedy" .)

I've seen this clue in The Times.

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