Nor quite. The word already had a clerical connotation before the NT. See the Theological Dictionary of the New Testament.
What word? Priest or presbyter? Cite the exact page in the Theological Dictionary of the New Testament.
It is also precluded by the Epistle to Timothy, in which St. Paul tells St. Timothy not to allow anyone to make an issue out of his young age:"Let no one despise you for your youth...Do not neglect the gift you have, which was given you by prophecy when the presbytery laid their hands on you."
I'm not sure I understand your point here. The Greek word in this passage is "presbyterion," and means body of elders. Again, elders are bishops. Timothy was not ordained by priests.
The order of priest came out of the chorbishops, who first served as presbyters alongside the Apostles and then took their place as bishops, the (parish) priesthood taking the role thus vacated.
My point is that there is no office of priesthood mentioned in the New Testament.
Priests are found in the epistles of St. Clement's (and the Apostles') contemporary St Ignatius, so it's not an innovation.
Please cite specific references. In Clements first ’s Letter to the Corinthians, which was a letter written from Rome to Corinth, we see that the Corinthian Church still viewed presbyters and bishops synonymously. Presbyters were not priests who were distinct from bishops as we see in Catholicism and Orthodoxy “For our sin will not be small, if we eject from the episcopate [office of bishop] those who have blamelessly and holily fulfilled its duties. Blessed are those presbyters who, having finished their course before now” (Clement, Letter to the Corinthians, 44, brackets mine). In Polycarp’s Letter to the Philippians he shows that their church was still two-tiered, and that presbyters were therefore not priests distinct from bishops. He said to be “obedient to the presbyters and deacons as to God and Christ” (Polycarp, Letter to the Philippians, 5). The Didache, which is a late 1st century Christian manual written by students of the apostles, shows that they believed in this two-tiered system as well, making no mention of presbyters being distinct from bishops: “appoint yourselves bishops and deacons worthy of the Lord” (Didache, 15). The Church historian, Philip Schaff remarks, “The Didache (ch. 15) knows only bishops and deacons, as local officers, the former being identical with presbyters” (Philip Schaff, History of the Christian Church, Volume 1, [Hendrickson Publishers, 2011], p. 493 n. 6).
Btw, "presbyter" is still the Greek word for priest, hence his wife is called "prebytera."
Modern Greek is different from New Testament koine Greek so your point is irrelevant, even if true.