occasion of sin
An external circumstance which of its own nature or because of man's frailty inclines and leads to sin.
An occasion is proximate if the danger of sinning is certain or probable, remote if such danger is slight.
It is absolute if of itself it leads us to sin, relative if only on account of weakness it becomes an occasion of evil-doing.
It is voluntary if it may easily be shunned, otherwise it is involuntary.
It is present if we have it with us without seeking it; otherwise it is absent.
There is no obligation to avoid a remote occasion, unless we foresee that it will soon be proximate.
But there is a positive obligation to avoid a voluntary proximate occasion, whether it be absolute or relative, present or absent.
New Catholic Dictionary