to hide: to put someone or something out of sight, or to keep a thing from being seen, known, or noticed.
At its simplest the word means to put something where it cannot be seen. A man buries treasure in a field, a servant sinks his master's money into the ground, Moses' parents keep their baby out of sight for three months, and twice Jesus slips away from a hostile crowd. In each case someone or something is deliberately moved beyond view.
The same verb reaches past physical hiding to whatever is held back from knowledge or notice. A city set on a hill "cannot be hidden," and good deeds cannot stay unnoticed forever. The meaning of Jesus' words is kept from his hearers, and God conceals his purposes from the clever while opening them to the childlike. Here nothing is buried, yet the thing is still kept from sight or understanding.
A related verb for covering (καλύπτω) drapes a covering over something, while this word moves it out of the eye's reach; the stronger compound (ἀποκρύπτω) leans further toward secrets kept on purpose. What ties every use together is intent: someone chooses to keep the thing from view, whether the thing is an object, a person, or a truth.