Should a second definition for a word be used over the first definition of another word? (Both appropriate words)

Say we have two words that essentially mean the same thing that can fit in a sentence. One of the words has a "primary" or first definition that allows it to fit in this sentence. The other word is a "secondary" or second/third definition of the word. Would it be more appropriate to use one over the other? Does it depend on who you are speaking to? I feel like it is better to use a "primary" definition over a "secondary" one.

When I say "primary" and "secondary" I am referring to any dictionary or source to define words that list multiple definitions for a word. Do any of these definitions take priority over others? Or is the first definition the most frequently used?

For example, ignorant can be defined as discourteous/rude:

this ignorant, pin-brained receptionist

What if you just used rude or discourteous instead of ignorant since someone would be more likely to understand that over knowing that ignorant can be defined as discourteous or rude? (Definition - Google <-- define: ignorant)

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.

If your goal is clarity, there is no doubt that you should use the word whose primary meaning is the one you intend.

Take this example:

John is gay.

You might mean he's cheerful or merry, but the sentence would no be interpreted that way because the primary meaning of "gay" is now "homosexual".

If it's perfectly clear from the context what meaning you intend, and there could never be any confusion amongst your audience, then use whatever word you prefer. But are you guaranteed that your intended audience will be the only audience, ever? And I wouldn't trust any set of readers anyways; something as simple as reading quickly can prevent the context from helping someone interpret something correctly. Your best bet is to assume misunderstanding and to attempt to mitigate it.

As noted in the comments, I would take the order listed by a dictionary with a grain of salt. If the primary meaning of a word for you does not match the dictionary you might want to think carefully about it.

If there is no way the meaning could be unclear, then it's purely a matter of style. The distinction between primary and secondary meanings varies greatly in strength.

Also, it could be that the word whose meaning is listed as primary is actually secondary in the context used and vice-versa for the word whose meaning is listed as secondary. So this can actually result in reduced clarity. For example, that the word "back" has a primary meaning as a part of the body doesn't mean "sit in the back of the bus" can ever be ambiguous or that a word with this as a primary meaning (such as 'rear') would be better.