Learn English – When is it appropriate, if at all, to use the suffix “ish”

Different dictionaries order their definitions in different ways. Some are diachronic, some order by senses, some by frequency of use - as with the Collins Cobuild.

The larger issue is that some words are used in specific situations, usual in certain contexts, which is more important than the order of their meanings as given in dictionaries.

For example: You can use the term "read" to mean "understand," as in, "I read you." This might be uncommon usage in an operating theater, but preferred in aeronautic communications.

Also: Word choice is often strongly influenced by surrounding words. More could be said on this subject if you provide the words and context in question.

The first uses the adjective financial as an adjective (as one would expect, I suppose).

The second uses the noun finance as an adjective.

You're allowed to use nouns in this way, but it is not as commonly done in cases where there is a well-known simple adjective, so we would expect the first to be more common, and it would probably be the better to go for, if you are choosing between using the two.

That said, business-y types seem to have a particular fondness for noun adjuncts. I think they've got the impression that they're more punchy or something. (If so, they are, IMO, wrong, but there's no accounting for taste).