good at cooking; good cook
Describes a person who is skilled in cooking. Can be used as a noun or na-adjective.
She is a good cook and always makes delicious food for me.
I want to learn from someone who is good at cooking.
A more common phrase meaning 'good at cooking', using 上手 as a na-adjective with the particle が. 料理上手 is a compound noun/adjectival noun that is slightly more compact.
Compound of 料理 (cooking) and 上手 (skillful).