noun
bald mountain; bare mountain; treeless hill
Refers to a mountain or hill with little or no vegetation, often due to deforestation, erosion, or natural barrenness.
その地域にははげ山が多く、緑が少ない。
There are many bald mountains in that area, with little greenery.
はげ山の頂上からは周囲の景色がよく見えた。
From the top of the bare mountain, we could see the surrounding scenery well.
Full kanji spelling using 禿げ; less common but still encountered.
禿げ means baldness (of a person) or a bald spot; はげ山 specifically refers to a mountain or hill that is bare of trees.
Compound of 禿げ (hage, 'baldness') and 山 (yama, 'mountain'). The spelling はげ山 is a common mixed kanji-kana representation.