ex ‧ tra ‧ ne ‧ ous /ɪkˈstreɪniəs/ BrE AmE adjective formal
[ Date: 1600-1700 ; Language: Latin ; Origin: extraneus 'foreign, strange' , from extra ; ⇨ ↑ extra- ]
1 . not belonging to or directly related to a particular subject or problem SYN irrelevant
extraneous to
Such details are extraneous to the matter in hand.
2 . coming from outside:
extraneous noises