intrigue

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A secret or underhand scheme; a plot.
2. n. The practice of or involvement in such schemes.
3. n. A clandestine love affair.
4. v. To engage in secret or underhand schemes; plot.
5. v. To effect by secret scheming or plotting.
6. v. To arouse the interest or curiosity of: Hibernation has long intrigued biologists.

Century Dictionary and Cyclopedia

1. To entangle; involve; cause to be involved or entangled.
2. To plot for: scheme for.
3. To practise underhand plotting or scheming; exert secret influence for the accomplishment of a purpose; seek to promote one's aims in devious and clandestine ways.
4. To have clandestine or illicit intercourse.
5. n. Intricacy; complication; maze.
6. n. Secret or underhand plotting or scheming; the exertion of secret influence for the accomplishment of a purpose.
7. n. A clandestine plot; a scheme for entangling others, or for gaining an end by the exertion of secret influence: as, to expose an intrigue.
8. n. The plot of a play, poem, or romance; the series of complications in which a writer involves his imaginary characters.
9. n. Clandestine intercourse between a man and a woman; illicit intimacy; a liaison.

Wiktionary

1. n. A complicated or clandestine plot or scheme intended to effect some purpose by secret artifice; conspiracy; stratagem.
2. n. The plot of a play, poem or romance; the series of complications in which a writer involves their imaginary characters.
3. n. Clandestine intercourse between persons; illicit intimacy; a liaison.
4. v. intransitive To conceive or carry out a secret plan intended to harm; to form a plot or scheme.
5. v. transitive To arouse the interest of; to fascinate.
6. v. intransitive To have clandestine or illicit intercourse.

GNU Webster's 1913

1. v. To form a plot or scheme; to contrive to accomplish a purpose by secret artifice.
2. v. To carry on a secret and illicit love or amour.
3. v. obsolete To fill with artifice and duplicity; to complicate; to embarrass.
4. n. obsolete Intricacy; complication.
5. n. A complicated plot or scheme intended to effect some purpose by secret artifice; conspiracy; stratagem.
6. n. The plot of a play or romance; a complicated scheme of designs, actions, and events.
7. n. A secret and illicit love affair between two persons of different sexes; an amour; a liaison.

WordNet 3.0

1. v. form intrigues (for) in an underhand manner
2. n. a crafty and involved plot to achieve your (usually sinister) ends
3. n. a clandestine love affair
4. v. cause to be interested or curious