This is so obvious. "I kill him!" "No, you wouldn't do that." "I, uh, I just said I did?" "No, you don't. You didn't start. You wouldn't do that."
Except when it's not obvious, right? "Wait a minute ... I tried to say 'I kill him' about ten times during that scene, and somehow I never got a chance. Or when I did, you treated it like my character was just thinking about it, not starting to do it."
I don't know anyone who likes their characters getting railroaded, which is why I think it's flatly Dysfunctional.
Openly or in secret
Railroading can be more subtle, done in secret, so that the other players, at first, don't recognize it: fudging dice rolls, or secretly changing the setting (putting the place where the characters don' want to go directly on their road, for example) or the other characters encountered (one common method is to decrease or increase the resistance to damage of the character's opponents to get the desired outcome from a fight) , or even using other powerful characters to force a specific course of action.
In any case, even if the methods are used in secret, the results are so evident that the other players will soon understand what it's happening, and they will lose any trust in the railroading player and in the rules of the game.
Control of a player-character's decisions, or opportunities for decisions, by another person (not the player of the character) in any way which breaks the Social Contract for that group, in the eyes of the character's player. The term describes an interpretation of a social and creative outcome rather than any specific Technique, but subtly or unsubtly entails the use of Force. Commonly responded to with various forms of My Guy tactics.