1. having the most spikes or sharp points
Usage: superlative form of spiky
2. most irritable or hostile in manner
Usage: informal

Examples

• The cactus in the corner was the spikiest plant in the garden.
• This rose bush has the spikiest thorns I’ve ever seen.
• The porcupine’s back looked spikiest when it felt threatened.
• He was at his spikiest during the morning meetings.
• Her spikiest comments came when she was under pressure.
• The hedgehog curled into its spikiest defensive position.