1. Having or as if having especially high-pitched spots
   "absence of peaky highs and beefed-up bass";
   - spiky
    
2. [Brit, informal] Unhealthy looking
   "His peaky complexion suggested a lack of sunlight";
   - sallow, sickly
    
3. Having or resembling peaks
   "The peaky mountain range dominated the horizon"

Derived forms: peakiest, peakier

See also: high, high-pitched, unhealthy