over the counter

Short definition from Wiktionary

Prepositional phrase

1. 1
   Through direct trade; outside a standard stock exchange.
2. 2
   Able to be obtained without a doctor's prescription.
3. 3
   Legitimately.

Adjective

1. 1
   Legal for sale or distribution without the requirement of a prescription.
2. 2
   Involving direct interaction between two parties without an intermediary, and denoting any market where items such as stocks or currency are bought and sold by direct arrangement between counterparties, or through a private broker, rather than on a public stock exchange or other exchange.