extraordinarily; uncommonly; exceptionally
Used adverbially to emphasize that something is far beyond the ordinary or average level. Often modifies adjectives or verbs.
彼は並外れて記憶力がいい。
He has an extraordinarily good memory.
今年の夏は並外れて暑かった。
This summer was exceptionally hot.
Alternate spelling with はずれて in kana; less common but still seen.
From 並 (なみ, 'average, ordinary') + 外れて (はずれて, the te-form of 外れる 'to deviate, be off'). Literally 'deviating from the ordinary'.