Origin according to wikipedia
The term's origin and etymology are unknown. Anime columnist John Oppliger has outlined several popular theories describing how the term would have stemmed from the name of anime heroines, such as Hotaru Tomoe from Sailor Moon (Tomoe is written as 土萌, relevant kanji is the same) or Moe Sagisawa from the 1993 anime Kyoryu Wakusei. Psychologist Tamaki Saitō identifies it as coming from the Japanese word for "budding". Ken Kitabayashi of the Nomura Research Institute has defined moe as "being strongly attracted to one's ideals" Kitabayashi has identified the word "moe" to be a pun with the Japanese godan (五段?) verb for "to sprout" moyasu (萌やす?) and its homonym "to burn" moyasu (燃やす?). Along the same line of thought, Kitabayashi has identified it to be a pun with the Japanese ichidan (一段?) verb for "to sprout" moeru (萌える?) and its homonym "to burn" moeru (燃える?), which mean "to burn" (in the sense of one's heart burning, or burning with passion). Galbraith states that the term came from 2channel in the 1990s, discussing female characters who were "hybrids of the Lolicon (Lolita Complex) and bishoujo (beautiful girl) genres". This describes exactly Hotaru Tomoe, and coincides with her height of popularity in 2channel, giving strength to the theory that the term stemmed from her name.
Comiket organiser Ichikawa Koichi has described Lum Invader of Urusei Yatsura as being both the source of moe and the first tsundere.
According to Hiroki Azuma, as Rei Ayanami became a more prominent character among fans, she "changed the rules" governing what people regarded as moe-inspiring. The industry has since created many characters which share her traits of pale skin, blue hair and a "quiet personality"
萌
―meanings―
show symptoms of
sprout
bud
malt
―on-yomi―
ホウ
―kun-yomi―
も(える)
きざ(す)
めばえ
きざ(し)
since it's a slang, i can't really say anything lol