Gremlin and Sandman

Gremlin noun - An imaginary being usually having a small human form and magical powers.

Sandman and gremlin are semantically related. In some cases you can replace term "Sandman" with "Gremlin", this nouns are similar.

Sandman noun - An elf in fairy stories who sprinkles sand in children's eyes to make them sleepy.

Gremlin and sandman are semantically related. Sometimes you can use "Gremlin" instead a noun "Sandman".