Is using the word "Rabb" (Lord) to describe someone's mastery of a particular field considered shirk (polytheism), knowing that the intention was not to associate partners with Allah?

It is permissible to use the word "Rabb" (Lord) for other than Allah when it is used in conjunction with an genitive construction (mudaf ilayh), not when used independently, whether the word is definite (with "al-") or indefinite. For example, "Rabb ad-dar" (Lord of the house) is permissible, whereas "So-and-so is a Rabb in the house" is not. The word "Rabb" is among the names exclusive to Allah Almighty. What is exclusive to Allah Almighty is the absolute use of "Rabb" without an genitive construction. However, with an genitive construction, its use is permissible, as in His (Allah's) saying: {Mention me to your Lord}. It is also correct to say, "So-and-so is the rabb of such-and-such knowledge," but it is not correct to say, "So-and-so is a rabb in knowledge." The forbidden word is not shirk that takes one out of the fold of Islam, even if it falls under the category of shirk in wording.