Deep-rooted and Hard shell

Deep-rooted adjective - Firmly established over time.

Hard shell and deep-rooted are semantically related In some cases you can replace phrase "Hard shell" with "Deep-rooted", this phrases are similar.

Deep-rooted and hard shell are semantically related in habitual topic. Sometimes you can use "Deep-rooted" instead an adjective phrase "Hard shell", if it concerns topics such as confirmed.