Biasest is the superlative form of the adjective "biased," which refers to a strong inclination towards a particular opinion or perspective. When attempting to convey the same meaning without using "biasest," some possible synonyms include prejudiced, partial, one-sided, slanted, skewed, influenced, or favored. Other synonyms that can convey a similar idea but with a different emphasis or nuance include subjective, tendentious, opinionated, partisan, or discriminatory. Depending on the context and intended tone of the message, different synonyms may be more or less appropriate or effective, but they all share a common thread of conveying a sense of unfair or unjust treatment based on personal biases.