セン, ひそ.む, もぐ.る, かく.れる, くぐ.る, ひそ.める
conceal, hide, lower (voice), hush
JLPT0 G13 S0 F5000
朁# is 兓 deep penetration + 曰 say/speech indicator → utterance that penetrates deeply. 潛 adds 水 water → penetrate deep into water in diving/submerging → *dive/submerge* → *lurk*; *hide* (← lie in wait in deep concealment) → *conceal*; *secret*; *latent*. Also, *hush*, *lower one's voice*, and *get/crawl into* (becoming hidden). Note that there is no etymological relation between the Shinjitai 潜 and the character 替.
[Full Kanji Etymology List]