有り得べき

プログレッシブ和英中辞典(第4版)

ありうべき【有り得べき】

それは有り得べきことだ
That's likely.／That's not impossible.

それは有り得べからざる話だ
That doesn't sound very likely to me.／That's an unlikely story!／〔皮肉に〕That's a likely story!

有り得べからざる事件が起きた
There was 「an unforgivable accident [an accident of the sort which should never have occurred].

出典　小学館「プログレッシブ和英中辞典(第4版)」