that they strive not about words - rather, “strive with words”: “not to have a (mere) war of words” (2Ti 2:23, 2Ti 2:24; 1Ti 6:4) where the most vital matters are at stake (2Ti 2:17, 2Ti 2:18; Act 18:15). The oldest manuscripts put a stop at “charging them before the Lord” (which clause is thus connected with “put them in remembrance”) and read the imperative, “Strive not thou in words,” etc.
to no profit - not qualifying “words”; but Greek neuter, in apposition with “strive in words,” “(a thing tending) to no profit,” literally, “profitable for nothing”; the opposite of “meet for the master’s use” (2Ti 2:21).
to the subverting - sure to subvert (overturn) the hearers: the opposite of “edifying” (building up) (2Co 13:10).