• uncredulous,
• uncredoulous,
• uncredilous,
• uncreadulous,
• uncredolous,
• uncredullous

• incredulity,
• disbelieving,
• hesitant,
• unconvincing,
• doubtful,
• dubious,
• suspicious,
• untrustworthy,
• questioning,
• wary,
• unsure,
• skeptical,
• incredible,
• incredulous,
• unbelieving.

The correct adjective form of the word "uncredulous" is "incredulous".

The plural form of the word "uncredulous" is "uncredulouses." However, please note that "uncredulous" is not a commonly used word, and alternative words like "skeptical" or "doubtful" are more commonly used in English.

The singular form of "uncredulous" is "uncredulous" as well. "Uncredulous" is an adjective that doesn't change when used in the singular or plural form.