un ‧ ac ‧ count ‧ a ‧ ble /ˌʌnəˈkaʊntəb ə l◂/ BrE AmE adjective formal
1 . very surprising and difficult to explain:
the unaccountable shyness she always felt in Louise’s presence
For some unaccountable reason, he arrived a day early.
2 . not having to explain your actions or decisions to anyone else OPP accountable
unaccountable to
Doctors still remain largely unaccountable to the public.