Definitions:

1. Reaching up to or immersed to the waist level, especially in water, mud, snow, or another substance. ADJECTIVE
   • They waded waist-deep into the river to catch fish.
2. Up to the waist. ADVERB
   • She stood waist-deep in the pool, waiving at her friends.

Synonyms:

• half-submerged
• halfway in
• partially submerged
• waist-high