out beyond one's depth

noun

1. 1. the distance from the top downward, from the surface inward, or from front to back
   2. perspective, as in a painting
2. the quality or condition of being deep; deepness; specif.,
   1. intensity, as of colors, silence, or emotion
   2. profundity of thought
   3. lowness of pitch
3. the middle part: the depth of winter
4. the far inner or inmost part: the depths of a wood
5. the deep or deepest part, as of the sea
6. 1. the most extreme degree, as of despair
   2. a low state or condition: shocked that their principles had fallen to such depths
7. reserve strength, as of suitable substitute players for a team