Espy and Hit upon

Espy verb - To make note of (something) through the use of one's eyes.

Hit upon and espy are semantically related In some cases you can use "Hit upon" instead a verb "Espy".

Hit upon verb - To come upon unexpectedly or by chance.

Espy and hit upon are semantically related in discover topic. Sometimes you can use "Espy" instead a verb "Hit upon", if it concerns topics such as happen upon, lay hands on, discover or be discovered.