Perfect Rhymes:
* Ingenious (though this is a positive word, so the contrast might be interesting)
* Ambiguous (less common, but similar in the sense of being unclear or misleading)
Near Rhymes:
* Suspicious
* Precarious
* Hilarious (not in meaning, but the sound is close)
Slant Rhymes:
* Dangerous (the "ous" sounds are similar)
* Courageous (same as above)
Creative Options:
* You could use a homophone like "disingenuous" for a humorous effect.
* Use a near rhyme in a metaphorical or figurative way to create a unique effect.
Ultimately, the best rhyme depends on the context and your creative intent.