Would you tell me whether I am right with my interpretation of the expressions in bold in the following sentences?
Thilo Sarrazin, a member of Germany's central bank, has stepped down. He now presents a problem for his political party, the Social Democrats, after claiming in a new book that Muslims are undermining German society.
step down = resign from office
undermine = destroy property or hinder normal operations; destabilize
Nationalization would undermine confidence in the financial system.
undermine confidence = to cause distrust
The sea is undermining the cliffs.
undermine = wash away
Thank you for your efforts.
Undermine here seems to me to be like weaken.