Resonating structures of phenoxide are-

In structure I and V –ve charge is on E.N. Oxygen, in other cases, it is on Less E.N Carbon hence they contribute less towards stability. And the –ve charge is localized.

Resonating structures of carboxylic acid-

Both the structures have –ve charge on oxygen and electron are delocalised too hence, the carboxylic acid is more stable and acidic than phenol.