atacar

To attack, in both the literal (military, physical) and figurative senses — attacking a problem, an argument, or even a plate of food colloquially (atacar la comida). It's used widely in sports and debate contexts too, for going on the offensive.

• El ejército atacó al amanecer. — The army attacked at dawn.
• Prefiero atacar el problema desde otro ángulo. — I'd rather tackle the problem from another angle.
• Los críticos atacaron la nueva ley. — Critics attacked the new law.

Using atacar for merely criticizing or disagreeing mildly — Spanish keeps a stronger, more aggressive connotation than some casual English use, so a polite disagreement is better phrased with criticar or cuestionar.