恒こう久きゅう的てき停てい戦せん

• 停てい戦せん

  停戦 is a general 'ceasefire' or 'armistice', while 恒久的停戦 specifically means a 'permanent' one.

• 休きゅう戦せん

  休戦 often implies a temporary truce or suspension of hostilities, whereas 恒久的停戦 is intended to be lasting.

Compound of 恒久的 (permanent) + 停戦 (ceasefire). 恒久的 is from 恒久 (permanence) + 的 (-like), and 停戦 is from 停 (stop) + 戦 (war).