Having or showing determined courage in the face of difficulties
Very interesting, especially because of being strange or mysterious
(of an argument or statement) seeming reasonable or probable
Less loud or strong compared to what is usual.
ADJECTIVE
Intriguing - Very interesting, especially because of being strange or mysterious
Jim found the study of physics very intriguing, because the more that was explained, the more seemed to be beyond comprehension - such as the origin of the universe.