Sontaku is one of the orthodox words. Since you can find it on an ancient historical chinese text as ”the Shijing” or ”Classic of Poetry”, it should be more appropriate to put it as ”a word that had long been used for ages.” There is also some use in Japan as early as 10 A.D., so it must had been passed down from China.
It used to mean ”simply surmise one's mind”, for expample, ”sontaku my mother's mind” or ”sontaku his intention of the action.” It appears that people recently use it to refer ” Pre-emptively placate one's boss by following an order that has not been given.”
おべっか、へつらいというか。上の者に気に入られようとして、その意向を推測する。ちょっと特別な時に使われるようになりました。しかし個人的にはその場合の表現として、斟酌の方がしっくりくるんと思うのです。 Or like ”kiss ass,” ”butter up.” They try to get in their boss surmising his intentions. It's got to be used on a special ocation. However, I personally feel Shinsyaku fits more as an expression in the case.
