skeptical

As a verb speculate

is to think, meditate or reflect on a subject; to consider, to deliberate or cogitate.

As an adjective skeptical is

having, or expressing doubt; questioning.

As adjectives the difference between objective and skeptical

is that objective is of or relating to a material object, actual existence or reality while skeptical is having, or expressing doubt; questioning.

As a noun objective

is a material object that physically exists.

As adjectives the difference between ambivalent and skeptical

is that ambivalent is simultaneously experiencing or expressing opposing or contradictory feelings, beliefs, or motivations while skeptical is having, or expressing doubt; questioning.

As adjectives the difference between ambiguous and skeptical

is that ambiguous is open to multiple interpretations while skeptical is having, or expressing doubt; questioning.

As adjectives the difference between skeptical and nonskeptical

is that skeptical is having, or expressing doubt; questioning while nonskeptical is not skeptical.

As adjectives the difference between skeptical and unskeptical

is that skeptical is having, or expressing doubt; questioning while unskeptical is not skeptical; having an open mind.