| arduous(adjective, hard, difficult, complex, intricate) |
| cosmopolitan(adjective, knowledge, refined, polished, experienced) |
| serious(adjective, hard, difficult, complex) |
| thorny(adjective, hard, difficult, complex, involved) |
| hard(adjective, difficult, complex, involved, complicated) |
| problematic(adjective, hard, difficult, complex, intricate) |
| esoteric(adjective, hard, difficult, complex) |
| involute(adjective, hard, difficult, complex) |
| classy(adjective, style, bright, delicate, superior) |
| suave(adjective, smooth, superior, polite, elegant) |
| multiskilled |
| worldly(adjective, cool, smooth, knowledge, smart) |
| knowledgeable(adjective, cool, significant, familiar, rational) |
| mature(adjective, sharp, familiar, wise, refined) |
| polished(adjective, smooth, fine, superior, proper) |
| advanced(adjective, superior, refined, easygoing, cultured) |
| well-bred(adjective, smooth, delicate, superior, proper) |
| experienced(verb, adjective, cool, sharp, superior) |
| civilized(adjective, smooth, reasonable, superior, familiar) |
| subtle(adjective, quiet, slight, fine, thin) |