Favoritism

BIAS

An unfair leaning toward one side might skew your judgment in this four-letter word.

"Favoritism" hints at unfairly preferring one thing over another, which directly points to "bias"—a tendency to lean toward or against something without good reason. The word itself is straightforward here, with no hidden wordplay or tricks, since "bias" is a common synonym for showing partiality. If you think of situations where someone gets special treatment, like a teacher favoring a student, "bias" fits perfectly as the answer.