how to ask if something is not true for an amount of time

basically I want to do this:

if (boolean is not true for one second) {
do stuff
}

How would i go about doing that?

Thanks in advance!

Do something like

public class BoolOverTime : MonoBehaviour {
	private float time;
	
	void Start() {
		this.time = 0.0f;
	}
	
	void Update() {
		if(!yourBoolVariable) { //Replace yourBoolVariable with whatever you want to test
			this.time += Time.deltaTime;
		}
		else {
			this.time = 0.0f;
		}
		
		if(this.time>=1.0f) {
			//Do whatever you want to do if yourBoolVariable was false for >=1s
		}
	}
}

Well you could do a timer to check within this one second.
So basically, when b_StartTimer is tru it checks for the boolean.

bool b_CheckWithinOneSecond = false;
float fl_Timer;
bool b_StartTimer = false;

if(b_StartTime)
{
   fl_timer += Time.deltaTime;

   if(fl_timer <1 && b_CheckWithinOneSecond)
   {
        // do something
    }
    if(fl_timer> 1)
     {
        // Reset Timer
        fl_timer = 0;
        b_StartTime = false;
     }
}