extraordinarily; uncommonly; exceptionally
Used adverbially to emphasize that something is far beyond the ordinary or average level. Often modifies adjectives or verbs.
He has an extraordinarily good memory.
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'.