Moral (as an adjective) means: “of, pertaining to, or concerned with the principles or rules of right conduct or the distinction between right and wrong; ethical: moral attitudes;; capable of conforming to the rules of right conduct: a moral being.”
Amoral, on the other hand: “not involving questions of right or wrong; without moral quality; neither moral nor immoral.”
In short, if it is not sentient, it cannot be “moral” (or immoral) – it can only be.
What examples of this are there? Non-living objects (a car, a baseball bat, a rock) are obvious. But also any “living” object which has no choice regarding “rules of right conduct” – plants, animals, bacteria, etc. In other words, based on the definition of Genesis 2, the only moral creatures in the universe were thus imbued by their Creator with the capacity to choose whether or not to follow “rules of right conduct”.
On earth, the only moral beings are humans. In the spiritual realm, angels (both fallen and unfallen (ie, they chose to not follow “rules of right conduct”)) and God are also moral beings.
A moral being can choose to utilize any amoral object in either a positive, negative, or neutral fashion. For example, I could take a rock or club and beat someone to death (as Cain did to Abel). Or I could put rocks in a pile as a memorial to God’s goodness (like Noah).
On their own, the rocks have no goodnesss or badness. Rocks from the same location could even be used for good and bad at the same time (Elijah’s confrontation with the prophets of Baal).
Why is the delineation between moral and amoral so important? Because many people like to take amoral issues and turn them into moral absolutes. In the realm of music, for example, we are called upon by God to sing praises to His name. No where is there a stylistic convention, formula, or edict issued in the Bible. Music has no moral value – it is the singer or instrumentarian who can use their skills in a positive or negative way.
With regards to dress styles, we are called upon to be modest in our attire (specifically written to women, but I believe the case can be made for it applying to men as well). God didn’t tell women to wear ankle-length, plain, full-sleeve, black dresses anywhere in the Bible. Clothes on their own have no moral value or implication: it is the wearer who can use clothing in a positive or negative fashion.
It is always up to the moral agent (in our case a man or woman) as to whether or not they use any object in a moral or immoral fashion. It is up to the eater whether or not he uses amoral food in a way consistent with God’s glory – whether he eats to excess and is a glutton, or whether he takes his food with thankfulness to the One who provided it.
If you are doing something (as a Christian), it must be done to the “glory of God” (1 Cor 10:31). The saint can never legitimately claim that if they commit a sin it was the object‘s fault: it is their own. Nor can any become more holy by means of an object, `And He said to them, “Are you so lacking in understanding also? Do you not understand that whatever goes into the man from outside cannot defile him, because it does not go into his heart, but into his stomach, and is eliminated?” (Thus He declared all foods clean.) And He was saying, “That which proceeds out of the man, that is what defiles the man.”` {Mar 7:18-20}
It is not what you eat (or drink), but what you do and how you respond with your time, energy, and life that matters.