noun-modifying (irregular)
finest quality; specially made
Used prenominally to describe something made with the utmost care and quality, often implying a special or custom production.
This is a specially made chocolate of the finest quality.
極製の万年筆を贈り物に選んだ。
I chose a specially crafted fountain pen as a gift.
Compound of 極 (ごく, 'extreme, utmost') and 製 (せい, 'made, manufactured').