| cryptic(adjective, obscure, dark, strange, uncertain) |
| occult(adjective, dark, strange, uncertain, mysterious) |
| unexplained |
| unsolvable(adjective, obscure, explanation, mysterious, unfathomable) |
| impenetrable(adjective, obscure, solid, dark, strange) |
| indecipherable(adjective, obscure, dark, uncertain, deep) |
| miraculous(adjective, superior, wonderful, marvelous, amazing) |
| perplexing(adjective, hard, dark, strange, uncertain) |
| preternatural(adjective, unusual, amazing, astonishing, astounding) |
| recondite(adjective, dark, strange, uncertain, mysterious) |
| supernatural(adjective, superior, marvelous, amazing, astonishing) |
| mystical(hard, delicate, strange, complex, tricky) |
| uncomprehensible |
| unmotivated |
| arcane(adjective, obscure, solid, strange, doubtful) |
| bewildering(adjective, hard, unclear, tricky, complicated) |
| confounding(adjective, hard, delicate, complex, tricky) |
| deep(adjective, hard, delicate, complex, tricky) |
| difficult(adjective, hard, obscure, dark, strange) |
| hidden(adjective, hard, obscure, solid, strange) |