In texts, it is common the meaning of an unknown word such as "inscrutable" can be guessed based on the context of the word. In the case presented the word "inscrutable" is used to describe the house a child is drawing, considering most children do not have impressive skills to draw, it can be inferred the house of the child is being described by the author as difficult to understand, and therefore the word "inscrutable" acts as a synonym of mysterious, puzzling or incomprehensible rather than impressive, beautiful or organic.
The term or name for word clues in a text that appear different because they are bolded, highlighted, italicized or written in a different font is typographical, which refers to the work of setting and arranging types and of printing from them; it pertains to the character and appearance of printed material.