When a variable is significant?

A variable, suppose X is significant at five percent level when the p-value associated with t-statistics is less than 5 percent.

Suppose, p-value is 0.049 meaning that X variable is significant at 4.9 percent level.

In other way, we can say that, if we reject the null hypothesis, the probability of committing type I error would be 4.9 percent. So we can reject null confidently as the probability of committing type I error is very small.