Espy and Run across

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

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

Run across verb - Come together.

Espy and run across are semantically related in happen upon topic. Sometimes you can use "Espy" instead a verb "Run across", if it concerns topics such as lay hands on.