scythe, suitability
剴 centers on cutting with a scythe-like tool, and by extension, the idea of being suitable or fitting—as if something is cut to the right measure. The two meanings are loosely connected through the notion of trimming or shaping to fit.
剴 combines 豈 (a phonetic component with an uncertain original meaning) and 刂 (knife), suggesting a cutting action. The exact historical development is uncertain, and the connection to 'suitability' may be a later semantic extension.
The left side 豈 looks like a complex tool with a drum-like top and a base, while the right side 刂 is a knife. Imagine a scythe-like blade attached to a sturdy handle, cutting through grass to make it suitable for use.
For ガイ, picture a guy using a scythe to trim the edges of a field, making everything fit perfectly: guy -> ガイ.
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appropriateness; adequacy; aptness; relevance