General Synonyms:
* Slanting
* Diagonal
* Inclined
* Askew
* Angled
* Sloping
* Skewed
* Indirect
* Circumspect
* Evasive
Figurative Synonyms:
* Allusive
* Implied
* Suggestive
* Covert
* Subtle
The best synonym will depend on the specific meaning you want to convey.
For example, if you're describing a line that is not straight, "slanting" or "diagonal" would be appropriate. If you're describing a statement that is indirect, "evasive" or "implied" might be better choices.