IPA: /ʌnˈjuːʒuəli/
KK: /ʌnˈjuːʒuəli/
In a way that is not common or typical; something that happens rarely or differently from what is expected.
She dressed unusually for the occasion, wearing a bright pink suit instead of the usual black dress.
Unusually → It is formed from the prefix "un-" (meaning not) and the root "usual" (from Latin "usualis", meaning customary or habitual) with the suffix "-ly" (meaning in a manner). The word "unusually" means in a manner that is not customary or habitual.
Think of 'not' ('un-') being added to 'usual' to remember that 'unusually' describes something that is not typical or customary.