What are sz and sn and ww respectively?

Sn stands for girl, sz stands for branch, wm stands for perfection.

Codewords include Chinese and English letters, punctuation marks, symbols, pinyin, icons and words. Refers to the secret language agreed upon by each other. Example: speaking code words. Contact in code. Whispering to each other, using an agreed word to represent a special meaning. A specific word or idiom used by a specific social group, especially as a means of communication, is a prearranged code word used to convey secret information, which is a metaphor for beating around the bush when speaking.