no chance of; definitely not possible
Expresses that something has absolutely no chance of happening or being true; a strong negative assertion.
っこない is a colloquial, emphatic way to say something is impossible. It's stronger than just using the negative form of a verb; it asserts that there's no way, no chance. You'll hear it in everyday speech, often with frustration or certainty.
It attaches to the ます-stem of a verb. For example, from できる (can do) you get できっこない (no way can do). From 行く (go) you get 行きっこない (no way will go). It's not used with nouns or adjectives directly.
This pattern is common in casual conversation but can sound blunt or even rude if used in formal settings. It's fine among friends or when you want to emphasize your opinion strongly.