cogitate
1. [ verb ] consider carefully and deeply; reflect upon; turn over in one's mind
Synonyms: deliberate
Related terms: chew_over debate take_counsel see premeditate cogitation
2. [ verb ] use or exercise the mind or one's power of reason in order to make inferences, decisions, or arrive at a solution or judgments
Synonyms: think cerebrate
Examples:

"I've been thinking all day and getting nowhere"

Related terms: reason plan relate associate think_about chew_over give judge concentrate study puzzle_over philosophize reason think think rationalize brainstorm think chew_over think_up think_out thinking mind cogitation thinker
Similar spelling:   costate
  cogitative
  cogitation