What does the suffix fit mean?

There isn't a suffix "-fit" in English that has a consistent, independent meaning. Words *containing* "fit" often relate to suitability, being appropriate or well-adjusted, but that's due to the root word "fit" itself, not a separable suffix. For example:

* Hand-fit: Means something is fitted by hand, implying a close and precise fit. "Fit" here is the main word, not a suffix.

* Sea-fit: Means suitable for sea travel. Again, "fit" is the main word.

If you encountered a word with "-fit" as a seeming suffix, please provide the word so I can give a more accurate explanation. It's likely that "fit" is part of the root or stem of that word, not a suffix with its own independent meaning.