tantamount

1. ADJ If you say that one thing is tantamount to another, more serious thing, you are emphasizing how bad, unacceptable, or unfortunate the first thing is by comparing it to the second thing. 无异于的[正式] [v-link ADJ 'to' n/-ing]

What Bracey is saying is tantamount to heresy. 布里斯正在说的无异于异端邪说。