早
ソウ, サッ, はや.い, はや, はや, はや.まる, はや.める, さ, さか, さわ, そ, わ
early, fast
JLPT4 G1 S6 F402
An abbreviated form of 朝 (rising sun; morning) → *pre-dawn darkness* → *early morning*; *early* → *move forward* (in time); *fast* → *hasten*; *accelerate*. Also, *rash/hasty* (← hasten). Compare the transition from early morning darkness to the idea of early/fast in 夙.
[Full Kanji Etymology List]