This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 葪 is uncertain. It visually contains 艹 (grass) and a lower part combining 角 (horn) and 刂 (knife), but the original semantic and phonetic roles are unclear.
The top 艹 suggests a plant, and the lower part looks like a horn 角 being cut by a knife 刂. Imagine a thorny plant with sharp horn-like spikes that can cut.
For ケイ, picture a thorny plant shaped like the letter K: K -> ケイ, and its spikes are as sharp as a knife.