fitting/suitable

Yes.

"fitting" is much more common in this context.

Both are grammatical and acceptable usage-wise, but both words can have a negative connotations when used like this. "Fitting" is often used to imply retribution, and "suitable" is cold-sounding. Moreover, the word "end" has negative connotations in itself. This might be better say something like:

"The dinner was a grand finale to Carter's 25 years with the company."

Thank you all for your help. I had a look at a few more dictionaries and I saw that "a fitting end", "It was fitting..." are pretty much set phrases. Oxford defines "fitting" as a synonym for "appropriate". Sometimes they can be interchanged, can't they? If something is fitting, then it is appropriate for a particular situation/occasion etc. Please correct me if I am wrong, but I think "suitable"

I don't think "fitting" implies retribution, because retribution has the connotation of vengeance, which inflicts incommensurate punishment, which is hardly fitting. English has the idiom "just deserts," and those are generally for deserved ill treatment. But not "fitting," which means appropriate to the situation, good or bad.

And I don't feel the temperature drop when I hear "suitable

AnonymousBoth are grammatical and acceptable usage-wise, but both words can have a negative connotations

I disagree 100%. "Fitting" here implies "satisfactory, pleasing."

Gene93Please correct me if I am wrong, but I think "suitable" is more often used when something is right for a particular purpose. Maybe there's some overlap.

There is an overlap, but when there are set collocations in the language, it sounds strange to native speakers if you substitute a synonym for one of the words in the phrase.

I have no issues w

Thank you, Alphecca Stars. That's what I meant. I have no intention of changing the set phrases/constructions. I wouldn't say though: "The manager should take fitting action if safety standards are not being met.". I would use appropriate here.

Gene93I would use appropriate here.

I would also consider appropriate. Suitable is a second choice.