For "narrow" meaning "not wide":
* Wide
* Broad
* Spacious
* Ample
* Expansive
* Vast
For "narrow" meaning "limited":
* Broad
* Wide-ranging
* Comprehensive
* Extensive
* Open
For "narrow" meaning "close-minded":
* Open-minded
* Tolerant
* Liberal
* Broad-minded
For "narrow" meaning "scarce":
* Abundant
* Plentiful
* Ample
* Sufficient
Please provide more context about the meaning of "narrow" in your sentence, and I can give you a more precise antonym.