腿了

(Tw) (Internet slang) too late, someone posted that already (supposedly from "lag" misspelled as "leg")

(completed action marker) / (modal particle indicating change of state, situation now) / (modal particle intensifying preceding clause)

to finish / to achieve / variant of 瞭|了[liao3] / to understand clearly

(of eyes) bright / clear-sighted / to understand clearly

unofficial variant of 瞭[liao4]

leg / CL:條|条[tiao2]

hip bone / old variant of 腿[tui3]