מַשְׂכִּיל maskil someone who is sensible, wise, insightful or prudent (as often in Hebrew, what is a noun in English is a participle). It is typical of the vocabulary of Wisdom Literature being especially frequent in Proverbs, Daniel and some Psalms (usually in cotexts dealing with teaching and wisdom) but it is rare in the prophets (the verb only appears 8 other times in all of the prophetic writings). Vocabulary like this links Amos to wisdom traditions.