adj

• (not comparable) Of a plant: producing spikes (“ears (as of corn); inflorescences in which sessile flowers are arranged on unbranched elongated axes”).
  "[T]he harvest maids began to look knowingly to their partners, who, taking the hint, sprang to their feet, hauled up their sweet abettors, were mated in a moment, and commenced a dance among the stubble, so brisk, that the tall harvest of spiky wheat, standing by, rustled and nodded to them on its golden rods."
• (comparable) Of a plant part: resembling a spike of a plant (see above).
  "Of this kinde, there is founde an other, the Spikes, eares, or torches wherof, are very dubble, ſo as in euery Spyky eare, in ſteede of the little knappes or heades, it bringeth forth a number of other ſmal torches, wherof eche one is lyke to the ſpike or torch of great Plantayne. […] The ſtalkes [of the third kind of plaintain] be creſted or ſtraked, and beare at the toppe fayre ſpiked knappes with white floures or bloſſoms, like the ſpykie knoppes of the middle Plantayne."

adj

• (figurative)
  "a spiky personality"
• (figurative)
  "It started with Ron [Phillips] soloing on "He Wasn't Talking to Me," a quiet and wistful ballad that segued into the upbeat and spiky "Give Me a Man Who's Glad to Be Gay." This was a pride anthem about being gay with a few nudges at those carrying their closets with them to the bars (Straight looking marine seeks/straight looking cop to please/How straight can they look/when they're down on their knees?)."
• (figurative)
  "I wondered if this meant he was a spiky Anglo-Catholic, which seemed a little unlikely, given that Norfolk's spiky hotspots are well-known."