Crossword Genius

Promised to go into the union (9)

Ross

I believe the answer is:

affianced

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

'promised' is the definition.
(synonyms)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Another definition for affianced that I've seen is " Betrothed".)

I've seen this clue in The Globe and Mail.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.