Cave: 穴
穴 means a hole or cave and sits at the top as あなかんむり. It suggests enclosed spaces in 窯 (kiln) and confinement in 窒 (obstruct) or 窮 (cornered, destitute); 窃 (steal) carries a more indirect sense of doing something secretly.
窃 has 9 strokes and 窮 has 15; keep the 穴 roof clear above the lower components.