睁 is the opposite of 闭 (bì, to close). Common collocations: 睁开 (zhēngkāi, to open eyes), 睁大 (zhēng dà, to widen eyes), 睁眼 (zhēngyǎn, to open one's eyes).
Left eye radical — indexing radical for 睁. A vertical-rotated rectangle with two interior bars, originally a sideways pictograph of an eye. Anchors 睁 in the seeing/eye-action family alongside 看 (look), 眼 (eye), 眨 (blink), 瞪 (stare). Marks the action as something done with the eye.
Right phonetic 争 — supplies the sound exactly (zhēng, no drift). Originally pictured two hands pulling at the same object, hence 'struggle, contend.' Combined image of 睁: the eye plus a struggle — the small effort of forcing eyelids apart in the morning. A vivid mnemonic that the English 'eyes struggling open' captures.