Select the odd one out

In an 'odd one out' word question, first identify the single feature — spelling, sound, or meaning — that most of the words share, then pick the one word that breaks that shared feature.

HAIR, FAIR, and PAIR all end in the letters '-AIR' and are pronounced with the same rhyming sound; none of them names a person — HAIR is a body part, FAIR is an adjective/event, and PAIR is a set of two items. LIAR, in contrast, ends in '-IAR' (not '-AIR'), is pronounced differently (rhyming with 'fire', not 'hair'), and is the only word here that names a person — one who tells lies.

• HAIR — ends in '-AIR', rhymes with the other two, and names a body part (not a person); it fits the shared majority pattern.

• FAIR — ends in '-AIR', rhymes with the other two, and is used as an adjective/for an event (not a person); it fits the shared majority pattern.

• PAIR — ends in '-AIR', rhymes with the other two, and denotes a set of two items (not a person); it fits the shared majority pattern.

LIAR breaks both the spelling/sound pattern and the semantic category (person vs. non-person) shared by the other three, so it is the odd one out.