intriguing

Concise Oxford English Dictionary © 2008 Oxford University Press:
intrigue

▶verb /ɪnˈtriːg/ (intrigues, intriguing, intrigued)

• 1 arouse the curiosity or interest of.

• 2 plot something illicit or harmful.

▶noun /ɪnˈtriːg, ˈɪn-/ 

• 1 the plotting of something illicit or harmful.

  ■ a secret love affair.

• 2 a mysterious or fascinating quality.

– derivatives
intriguer noun,
intriguing adjective,
intriguingly adverb.

– origin C17: from Fr. intrigue ‘plot’, intriguer ‘to tangle, to plot’, via Ital. from L. intricare (see intricate).