hi! so basically, there are a lot of kanji out there that all seem to mean ‘action’ in one way or another; and I can’t tell which context to use each in (I’m assuming each word has some sort of nuance and that they aren’t just all synonyms)
the words in question are:
koudou(行動)
katsudou(活動)
sayou(作用)
shigusa(仕草)
how do you differentiate between these? thanks for your help~