If you describe something such as a desire or force as irresistible, you mean that it is so powerful that it makes you act in a certain way, and there is nothing you can do to prevent this.
It proved an irresistible temptation to Bob to go back.
事实证明,回去对于鲍勃来说是一种无法抵抗的诱惑。
If you describe something or someone as irresistible, you mean that they are so good or attractive that you cannot stop yourself from liking them or wanting them.
The music is irresistible.
这段音乐非常有感染力。