oppose, offend, run counter to
攖 centers on active resistance: opposing, offending, or running counter to something. The meanings share the idea of pushing back or acting against.
攖 combines 扌 (hand) with 嬰, which likely contributes the sound and may relate to encircling or entangling, suggesting a hand opposing or offending. The exact historical development is uncertain.
The hand radical 扌 beside 嬰 suggests a hand pushing against something encircling or entangling: opposing and offending by force.
For エイ, imagine an 'A'-shaped hand opposing a tangled mess: 'A' -> エイ, and the hand runs counter to the entanglement.