This question has been asked and answered many times and many ways. I’ve looked into this a fair bit, but ultimately haven’t found conclusive answers. My hope is that someone here has insight they can share.
We live in a material world, and thus the easiest thing for us to recognize is our body. I can see with my eyes, move with my muscles, feel with my nerves, etc. Easiest to grasp. However, I can’t observe what functions the soul and spirit are doing, nor which functions are done by which. As such, my only concept of a soul or spirit are from the ideas of the metaphysical, and chiefly the Bible.
The Bible is translated into English, and thus the words it uses may not be 1-to-1 synonyms with the original Hebrew/Greek. Luckily, we have some degree of record of what was written (my favorite example being Matthew 5:5 “Blessed are the meek for they shall inherit the earth.”, as the Greek word used was “praus” (πραεῖς) was used to describe trained warhorses. They were not “humble” or “timid”, but rather fierce, courageous, and powerful, but likewise disciplined, and submissive to/dependent on their masters). According to what I’ve found, the Hebrew and Greek words used most often for “soul” were nephesh and psuche respectively, the latter of which is where we derive “psyche, psychology”, etc. Alternatively, the Hebrew and Greek words used most often for “spirit” were ruach and pneuma respectively, the latter of which is where we derive “pneumonia, pneumatics”, etc. Both words, however, in their original meaning (at least for Greek [and Latin, interestingly]) had association with air, breathe, and life. This could be because both air and metaphysical things were unable to be seen, and parallels were drawn, or perhaps there was metaphorical significance. Afterall, in Genesis 2:7 it is noted that God formed man from the dust of the ground, and “breathed into his nostrils the breath of life; and the man became a living being.” However, the words being used don’t seem entirely definitive on what exactly the distinction is, nor exactly what each entails. One site (https://www.christiancourier.com/articles/526-soul-and-spirit-whats-the-difference) indicates “soul” was used for a person, life, and the mind (intellect and emotion), while “spirit” was used for air, non-physical being, a person, a synonym of soul, and a mental state/disposition.
One thing I’ve heard that hasn’t fully settled with me is the explanation that “we are a spirit, we have a soul, and we’re in a body”, specifying that the spirit is “what we are” and allows us to connect to God, while the soul is our intellect, will, and emotions. This just seems bizarre to me, particularly when considering God. God (I assume the Father) many times is denoted as feeling emotions, including but not limited to anger at the Israelite with the golden calf (Exodus 32:10). However, emotions are to my findings most heavily associated with the Holy Spirit, including but not limited to the fruit of the Spirit (Galatians 5:22). I furthermore found a site that goes into depth on emotions and the Holy Spirit (https://bible.org/seriespage/holy-spirit-and-our-emotions). While this site seems to do fairly well at separating soul and spirit and defining them somewhat distinctively, there seems to at times be overlap, and it clashes with “conventional” ideas on the two aspects (or at least many other “answers” I’ve found. And animals are furthermore an interesting inclusion, as they have more animacy and sentience than plants or the like, but are not sapient like people. Is their sentience strictly physical, and if so is ours as well? Or do they indeed have souls, awarding them various metaphysical traits such as sentience, while not quite having sapience? I would not think they would have spirits, if only because animals were not said to have been made in God’s image (this opens an interesting tangent, but I’ll save that for another question).
I’m interested in understanding what exactly the soul and spirit each do, especially in contrast and tandem with the body. Personally, I’m not of the mind that the parts of us are separate, but rather than they can all affect each other. I believe “mind over body” or otherwise willing to get better (when sick or otherwise) helps your body to actually do so whereas having little will to get better often results in deterioration. Likewise, treating your body well can benefit your soul/spirit, and treating your body poorly (especially in sexual matters) can cause your soul/spirit distress.
Are the ruminations or understanding of senses (sight, hearing, etc.) strictly physical, belonging to metaphysical, or is there overlap? Are emotions from the spirit or soul, or are there different aspects of emotions that reside in each? What about intellect, regarding reason, or abstract thought? Is willpower (the ability to determine or otherwise make a choice beyond strictly chemical reactions to stimuli) a trait of the spirit or soul? While the body could be considered to be understood rather well, perhaps some mental functions that could seem strictly physical are in fact metaphysical.
Simply: what defines the body, spirit, and soul, specifically individually, but also where they compliment each other.