asomar

To poke out, lean out, or start to come into view — asomarse a la ventana (to lean out the window), asomar la cabeza (to stick your head out), or used for something gradually appearing (el sol asoma por el horizonte). It's about a partial, often brief appearance, distinct from aparecer's more complete "to appear."

• Se asomó a la ventana para ver quién llamaba. — She leaned out the window to see who was knocking.
• El sol empezaba a asomar entre las nubes. — The sun was starting to peek out between the clouds.
• No te asomes tanto, te vas a caer. — Don't lean out so far, you'll fall.

Confusing asomar (to poke or lean out, partial and brief) with aparecer (to appear/show up, more complete or sudden) — asomar la cara means just showing part of your face, not making a full appearance.

Often confused with aparecer.