Definition: A person who is regarded as 'hot' only because they are close by or seen everyday.
ex 1- " Joan is hot eh?"
" No she isn't. It's just because she working in our office, your suffering from proximity hotness..."
ex 2 - That dude is hot eh?"
" No he isn't. It's just because your in jail, your suffering from proximity hotness...
Other examples: office hot, school hot, some milfs, in rare occasions 'girl next door' is just proximity hotness or the dreaded jail hot.
Proximity hotness is also effected by the talent of hotness you see day to day. Less talent= more susceptible to proximity hotness.