陌陌 Origin — Chinese Character Wiki

Mòmò

Momo

mò foot path between rice fields

Phonosemantic compound. 阝 represents the meaning and 百 represents the sound.

阝 Meaning component

fù hill, place

百 Sound component

bǎi one hundred

Change in sound

陌 and 百 don't sound similar in modern Mandarin due to historical phonetic changes. They were more similar in Middle Chinese.
陌 maek
百 paek

	Middle Chinese	Old Chinese	Gloss
Baxter-Sagart	maek	[m]ˤrak	path between fields