Discreet MP, maybe that excludes Mr Paisley? (7)

I believe the answer is:

politic

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

'discreet' is the definition.
(I've seen this in another clue)

I can't explain the remainder of the clue.

(Other definitions for politic that I've seen before include "Prudent, judicious" , "Advisable" , "Shrewdly tactful" , "Prudent, sagacious" , "artful" .)

I've seen this clue in The Independent.

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