Spikiest is an adjective that means pointed, having spikes or thorns, or being sharp. Some antonyms, which are words that have opposite or contradictory meanings to spikiest, include smooth, flat, blunt, dull, or soft. Smooth refers to something that is even, without roughness or bumps, while flat means having an even surface or being level. Blunt refers to something that lacks sharpness or is not pointed, and dull means lacking sharpness or brightness. Soft refers to something that is gentle or yielding, opposite of the hardness or sharpness associated with spikiest. Overall, these antonyms show that spikiest is an extreme and specific term, and there are many alternatives that describe different qualities.