A child who is very attached to their father and prefers him over the mother. Used for both boys and girls.
See also: お父さん子 (おとうさんこ)
Our daughter is a total daddy's girl and always follows her dad around.
My son is a daddy's boy, so he always plays with his father on days off.
Compound of お父さん (father) + っ子 (child, with emphatic gemination). The っ子 suffix indicates a strong association or attachment.