Straight-thinking is a term that refers to someone who thinks logically and rationally, without being biased or swayed by emotions. Some synonyms for this term include clear-headed, level-headed, rational, objective, and analytical. Clear-headed connotes an ability to think through complex situations in a straightforward manner, while level-headed implies a calm and collected approach to problem-solving. Rational refers to a logical thought process, while objective suggests a lack of personal bias or subjective influence. Finally, analytical describes an approach that involves breaking down complex problems into smaller components and analyzing them systematically. Overall, these synonyms all convey the same idea of a person who approaches problems with a rational, logic-based mindset.