Counteract (kountr-kt), v. t. [imp. & p. p. Counteracted; p. pr. & vb. n. Counteracting.]
To act in opposition to; to hinder, defeat, or frustrate, by contrary agency or influence; as, to counteract the effect of medicines; to counteract good advice.
Shades of meaning
Fernald has no entry of its own for counteract; he lists it under hinder.
He lists it without comment; the entries above explain its neighbors.