The best replacement for proximity is close proximity.

The best alternatives to proximity are rated as following:
★★★★★  close proximity
★★★★★  nearness
★★★  vicinity
★★★  similarity
★★★  propinquity
★★  mifare
★★  smart card
★★  globality
★★  rfid
★  proximity
★  estimote
  smart cards

Your alternative for proximity is not listed? Suggest!
Speaking about proximity, one probably shouldn't forget about intimacy.

Other search terms related to proximity and their ratings are:
★★★★★ intimacy
You have in mind a companion for proximity and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of proximity in all years. Click on graph for more.
proximity
close proximity
nearness