Kei a ... mō te ...
1. accomplished, adept, expert, gifted, masterly, skilful, skilled, talented, proficient - an idiom to indicate that someone is accomplished at something.
Kei a ia mō te whakatangitangi i te pūtōrino. / She's great at playing the flute.
Synonyms: waewae kai pakiaka, tareka, kei a [koe] mō te ..., toa, ringa rehe, riwha, taea