What does it mean to be unequally yoked in a relationship?

When oxen are unequally yoked, they cannot perform the task set before them. Instead of working together, they are at odds with one another.

What is the biblical meaning of Equally Yoked?

Basically, it means dont marry someone who isnt the same religion or who does not share the same religious beliefs. In other sections of the bible, it says the unbelieving spouse becomes a believer by proximity to the believing spouse(1 Corinthians 7:14 and (1 Peter 3:1–6).