Holy Spirit is a mistranslation of the Greek phrase in question. The first word Holy is correct. The second word Spirit is obviously incorrect. Heres a simple way to demonstrate the point.
Suppose I were describing to you a particular family consisting of husband, wife, and child. But instead of using the terms husband, wife, and child or even father, son, and mother I used the following terms: The father, the son, and the HUMAN BEING.
This kind of language DOESNT MAKE ANY SENSE. Neither you nor anyone else would ever make such a ridiculous statement - ridiculous because ALL THREE OF THEM are human beings. To refer to ONE of the three members as the human being would - if anything at all cast doubt as to whether the first two are human. Secondly, one of the main functions of a title is to provide some kind of conceptual distinction between various members. If the Bibles language fails to provide distinctions between the three members, it thereby undermines the biblical basis for Trinitarianism. I'm a Trinitarian myself.
So heres the problem. Mainstream Christianity regards ALL THREE members as spirit (and holy). Thus the term Holy Spirit applies to all three of them. Hence the phrase Father, Son, and Holy Spirit, is just as ridiculous as saying of a human family, The Father, the Son, and the Human Being. The only way to solve this is to acknowledge that "Spirit" is a mistranslation of the Third Person's title.
The Greek term (pneuma) - traditionally mistranslated Spirit - has one other possible meaning breath/wind. (The Greeks conflated breath/wind into one word pneuma even though they are two separate words in English). No theologian would deny that the Greek OT uses that term at least 100 times to denote breath/wind, and ditto of ruach (the Hebrew version of the Greek term pneuma).
The PROPER translation of the relevant passages, then, is Father, Son, and the Holy Breath/Wind. You can picture the Trinity as three physical Persons the Father seated on a throne, the Son seated at His right hand, and the Holy Wind/Breath continually exuding as smoke, wind, and Fire from their nostrils and mouth toward the earth as portrayed clearly in Psalm 18 (traditionally known as the PROCESSION of the Third Person from the Father and the Son to the earth). And they saw what seemed like tongues of fire descending from heaven
Several biblical contexts CLEARLY AND BLATANTLY confirm the translation Holy Wind. Lets consider just one example for now. On the Day of Pentecost
they heard the sound of a mighty rushing wind. And they were all filled with the Holy Wind. Here the CONTEXT confirms what we already should have known - we should have known it from the father-son-wife analogy I gave you above - that Holy Spirit is an obviously, blatantly incorrect translation of this passage.
Significant because the whole case for the claim that God is a nonphysical substance called spirit rests about 99% on the (mis)translation Holy Spirit. When we translate the term properly as the Holy Breath/Wind, it becomes apparent that 99% of the biblical data refers to God using physical language.
Ill end with this. As early as 200 A.D. the church father Tertullian the man credited with inventing the word Trinity insisted that God is a physical being biblically entitled the Holy Wind/Breath and he insisted that the term Spirit was born of Platos philosophy, not of Scripture. Cheers.