Can 谢谢 be abbreviated to a single syllable 谢? Is it meaningful to say "谢" only? Google Translate implies that it may also mean "wither". I want to use it to say "thanks" instead of both characters.

I am looking for single characters that I can use for some mandarin emojis, one of which is to mean "thankyou".
You can say 谢了 to mean thanks.