आपका āpkā

आप āp (hindi)

You (to a superior, a stranger, his father).
(reflective pronoun) Self, himself, oneself, yourself, themselves...

का kā (hindi)

का denotes one of the under-mentioned relations between a Noun or a Pronoun and another Noun which follows the former. If the Noun that follows is Feminine (singular or plural), का changes to की; if it is Masculine and Plural, or has an oblique form, का changes to के.

• Possession and relationship.
• Material or composition.
• Worth and measure (space or time).
• Source, origin, cause.
• Subject (doer of an act).
• Object (of an activity).
• Part of a whole.
• Purpose.
• Characteristic.
  (A Basic Grammar of Modern Hindi)