noun
deceased parent
A respectful and somewhat formal term for a parent who has passed away. Often used in contexts of remembrance or legal matters.
亡き親の遺影に手を合わせた。
I put my hands together in prayer before the portrait of my deceased parent.
亡き親の教えを今でも大切にしている。
I still cherish the teachings of my late parent.
亡母 specifically means 'deceased mother', while 亡き親 can refer to either parent.
Compound of 亡き (naki, 'dead, deceased', the classical attributive form of 亡し) and 親 (oya, 'parent').