English Reference
adjective · noun

unfamiliar

adj. · n.
US /ˌənfəˈmɪɫjɝ/ UK /ʌnfəmˈɪliə/ un·fa·mil·iar

  1. 01 B2 Upper Intermediate

    adj.not known or recognized because you have not seen or experienced it before.

    adj.not known or recognized; lacking the quality of being familiar through previous encounter or experience.

    Simple

    The city felt scary at first because all the streets were unfamiliar to me.

    In context

    Walking through the dense fog, he found himself in an unfamiliar neighborhood where even the architecture seemed alien and unsettling.

    Usage

    Often followed by the preposition 'to'.

  2. 02 B2 Upper Intermediate

    adj.not knowing much about a particular subject or how to do something.

    adj.not having knowledge or experience of a specific subject, system, or practice.

    Simple

    I am unfamiliar with this computer program, so I might need some help.

    In context

    The new manager was largely unfamiliar with the technical nuances of the project, necessitating a comprehensive briefing from the engineering team.

    Usage

    Usually followed by the preposition 'with'.

    unacquaintedignorant
    conversantversed
  3. 03 C2 Proficiency Literary

    n.a person that you do not know.

    n.a person with whom one is not acquainted. This nominal use is significantly less common than the adjectival form.

    Simple

    The dog barked loudly at the unfamiliar standing at the gate.

    In context

    In the quiet village, the arrival of an unfamiliar was always met with a mixture of curiosity and guarded silence.

    Teacher's tip

    This noun sense is rare in modern speech; students should use 'stranger' in almost all contexts.

Coe said the idea was “not as unfamiliar territory as people tend to think”.

Al Jazeera· 15 Aug 2026

The appeal of the Jonas Brothers, and in this case only one of them, was unfamiliar territory.

The Guardian· 14 Aug 2026

From un- + familiar.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated