Semantics is about the meaning of a word, phrase, etc. So sure, we're talking about what a word means. And its meaning isn't ambiguous. Neither is the usage. A felony isn't a particular act. Murder, theft and any number of observable acts are felonies.
anyone committing a felony is a felon even before conviction
No. Supra and prior. You're just wrong, no matter how convicted
eek
you are on the point.
Any felony committed makes the person a felon, end of story.
A felony is a conviction related to an act. It isn't the act. A given act against code will typically be termed an infraction, or a misdemeanor, or a felony. The designation is dependent on a number of factors. The same act may have a different designation depending on those factors.