| Answer | Crossword Clue |
|---|---|
| ART | Notoriously hard thing to define |
| CAMP | Notoriously hard-to-define aesthetic style |
| ELUSIVE | Hard to define |
| ELUSIVE | Hard to define. |
| XFACTOR | Hard-to-define element |
| XFACTOR | Hard-to-define influence |
| obscurest | Hard to make out or define; vague |
| SEX | Hard-to-define word of recent times |
| elusory | eluding clear perception or complete mental grasp; hard to express or define |
| elusive | eluding clear perception or complete mental grasp; hard to express or define |
| THEXFACTOR | Hard-to-define element, or a hint to what can precede each last word in answers to starred clues |
