is it possible to disable a function inside a script, currently im making a large script for multiple items that only need say a rigidbody added or destroyed after a few seconds, so i have a list of actions, effects and i also have either a trigger or collider as the activation of the script, is their a way to say only do one funcion so say i use a triiger as the activation but i also have a collider on the same object but dont want that tostart the script
That makes not much sense. A function can’t be disabled. A function is something like a hammer. It can be used (functions can be called), but you can’t disable functions. If you mean you want to prevent Unity from calling a certain callback function like Update, Start, OnCollisionEnter, OnEnable, … then the answer is: in some cases 
If you disable the script, Unity doesn’t call Update and collision handling functions, but some are still called like OnBecameInvisible, OnBecameVisible.
So to sum up: You can’t disable a single callback, but you can disable the whole script.
Usually you would create multiple scripts for different tasks. putting everything into one script has several disadvantages. It’s getting long and messy. Most the time you can’t even find a proper name for it since it does several things. When you write such highly specialized scripts they can hardly be re-used in other situations.
Try to modularize your script into smaller parts. That’s the point of Behaviours. You just attach a Behaviour to a gameobject to change / modify it’s behaviour or add a new / additional behaviour.