Feather-headed and Half-baked

Half-baked and feather-headed are semantically related In some cases you can replace phrase "Half-baked" with "Feather-headed", this phrases are similar.

Half-baked adjective - Showing or marked by a lack of good sense or judgment.

Feather-headed and half-baked are semantically related in foolish topic. You can use "Feather-headed" instead an adjective phrase "Half-baked".