Cosmonautic pertains to anything that is related to the exploration and scientific study of space. Some synonyms for cosmonautic include astrological, aeronautic, astronomical, and spacefaring. Astrological refers to the study of celestial objects and their influence on human affairs, while aeronautic pertains to the science of flight and aircraft design. Astronomical, on the other hand, is concerned with the study of celestial objects and their physical properties and behaviors. Lastly, spacefaring pertains to the capability of traveling and exploring space. These terms are often used interchangeably with cosmonautic, particularly in discussions that involve space exploration and scientific research.