楞 has two readings: léng (variant of
棱, 'edge / ridge'; also in
楞迦 Lengjia, the Lankavatara Sutra) and lèng (variant of
愣, 'be stunned / dazed'). The lèng reading is far more common in everyday text — when you see
楞 in a sentence about reaction or emotion, it's lèng.