also: ざあざあ
adverb, adverb taking the 'to' particle
heavily (raining); pouring; rushing water
Describes heavy rain or water flowing forcefully and noisily. Often used with 降る or 流れる.
外はザーザー雨が降っている。
It's raining heavily outside.
川
The river water is rushing loudly.
adverb, adverb taking the 'to' particle
with white noise; buzzing; static
Used for continuous background noise like radio static, TV snow, or a buzzing sound. Less common than the rain sense.
ラジオからザーザーと雑音が聞こえる。
I can hear static noise from the radio.