ヨク, あ.びる, あ.びせる, えき, さこ
bathe, be favored with, bask in
JLPT2 G4 S10 F1136
As per 谷# (cavity) + 水 water → submerge oneself in a water-filled cavity such as the base of a waterfall, or a bathtub → *bathing* → *pour* (water); *shower*; *immerse oneself* (in an activity). Other extended meanings from "pour" include *heap upon*; *bask* (in sunshine); *receive/be subjected to* and *under fire*.
[Full Kanji Etymology List]