stare
倪 centers on a fixed, intent gaze: staring at something or someone with focused attention.
倪 combines 亻 (person) with 兒, which likely contributes the sound and may relate to a child or smallness, but the exact historical development of the 'stare' meaning is uncertain.
A person 亻 beside 兒 (which looks like a child with a large head and legs) stares intently, as if watching a child closely.
For ゲイ, imagine a person staring at a gate: gate -> ゲイ, and their gaze is fixed on it.