KanjiJLPT N1
Excuse

excuse, dismissal

Mnemonic

You snatch the sun out of the sky with a hook and trap it between your legs. Your excuse? 'I just needed more daylight!' But the sun wriggles loose, freed from your grip—excused from captivity, it rockets back into the heavens.
Additional thoughts
Picture yourself literally hooking the sun and clamping your legs around it like a wrestler. The sun escaping = being excused/released from obligation. The desperate excuse you shout up at the sky cements the keyword.
Quick recall
A hook yanks the sun between your legs, but it's excused from your grip and escapes.

Details

The keyword for 免 is excuse. This kanji carries the meaning of being released from an obligation, duty, or burden—essentially being let off or exempted from something. It can convey the sense of dismissal from a position, avoidance of something undesirable, or being pardoned and forgiven. At its core, it represents the idea of being freed from responsibility or escaping an unwanted situation.
On'yomi
めん
Kun'yomi
まぬか.れる、まぬが.れる