noun
Refers to a customer who frequently patronizes a particular shop or business.
あの店の常得意は、いつも同じ席に座る。
The regular customer at that shop always sits in the same seat.
彼はこのレストランの常得意で、週に三回は来る。
He is a regular at this restaurant, coming three times a week.
常連 is a more common and casual word for 'regular customer'. 常得意 is slightly more formal and less frequent.
Compound of 常 (じょう, 'usual, regular') and 得意 (とくい, 'customer, client'). The exact historical derivation is uncertain.