(ש"ע) ספקן

n. uncertain person, person with doubts

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Noun
1. someone who habitually doubts accepted beliefs
(synonym) skeptic, sceptic
(hypernym) intellectual, intellect
(hyponym) doubting Thomas
(derivation) doubt
2. a person who doubts truth of religion
(synonym) agnostic
(hypernym) nonreligious person
(derivation) doubt

(n.)
One who doubts; one whose opinion is unsettled; one who scruples.
  

     redoubt     obtrude