Proximity, propinquity are often used almost interchangeably to denote nearness.
Proximity, however, commonly implies simple and often temporary nearness in space; it may be used with reference to either persons or things found in the same vicinity or neighborhood.
Propinquity may imply proximity, but it then usually distinctively suggests closeness, sometimes even contact.
But it is more often used as proximity is not, to imply nearness in relationship or closeness in association, in age, or in tastes or even closeness in time.