Xenophobia is the fear or dislike of anything which is perceived as being foreign or strange. It is an expression which is based on the perception that a conflict exists between an in-group and an out-group and it may manifest itself in suspicion of one group's activities by members of the other group, a desire to eliminate the presence of the group which is the target of suspicion, and fear of losing a national, ethnic, or racial identity.

अज्ञातव्यक्तिभीति को "विदेशियों या अजनबियों अथवा उनकी राजनीति या संस्कृति से घृणा या डर" के रूप में परिभाषित किया गया है। इसे अंग्रेजी में ज़ेनोफोब कहते हैं जिसकी उत्पत्ति यूनानी शब्द ξένος (जीनोस), जिसका अर्थ है "अजनबी", "विदेशी" और φόβος (फोबोस) जिसका अर्थ है "डर".