A clue or a hint is a piece of information bringing someone closer to a conclusion[1] or which points to the right direction towards the solution.
The word evolved to have its current meaning in part because of the common motif in mythology and folklore of using a ball of thread to aid in escaping a maze.
Clues were introduced to detective fiction by Arthur Conan Doyle's Holmes stories, and they remain a staple of the genre today.
[13] A 1971 study classified clues for second language readers into three categories: intra-lingual, inter-lingual and extra-lingual.
For example, an observant Jewish person may say something like “The light is bothering me,” or “The Synagogue’s door is unlocked,” as hints to the Shabbat goy to fulfill their voluntary obligations.