What does the word zainly mean?

The word "zainly" is not a recognized word in standard English. It's likely a misspelling or a word from a specific dialect or slang.

If you heard it in a particular context, it would be helpful to know:

* Where did you hear it? (A specific region, online, in a book, etc.)

* What was the context? (What were people talking about?)

With more information, I might be able to guess what the speaker meant.