Individual who is selling a put option.  The put writer is obligated to purchase the option if the put buyer chooses to sell the option.
Related information about put writer:
- Put option - Wikipedia, the free encyclopedia
 The put writer believes that the underlying security's price will rise, not fall. The   writer sells the put to collect the premium. The put writer's total potential loss is ...
 
- What is put writer? definition and meaning
 Definition of put writer: Individual who is selling a put option. The put writer is   obligated to purchase the option if the put buyer chooses to sell the option.
 
- Put Writer
 Definition of "Put Writer". An individual who sells put options for a fee or premium.   The writer of a put option is then obligated to purchase the underlying security ...
 
- Introduction To Put Writing
 Sep 17, 2009 ... Instead of using the premium-collection strategy, a put writer might want ... In this   case, the put writer would sell a put at a strike price below the ...
 
- Put Writer Payoff Diagrams | Finance | Khan Academy
 If I were the party writing a put option, I would be looking to insure some other   party who didn't want his stock to go down too much and who wanted to unload   his ...
 
- Uncovered Put Write Explained | Online Option Trading Guide
 Profit for the uncovered put write is limited to the premiums received for the   options sold and unlike the covered put write, since the uncovered put writer is   not ...
 
- Put option: Definition from Answers.com
 The put writer believes that the underlying security's price will rise, not fall. ... The   put writer's total potential loss is limited to the put's strike price less the spot and ...
 
- Cash-Secured Put
 Unlike a naked put writer whose only goal is to collect premium income, a cash-  secured put writer actually wants to acquire the underlying stock via assignment.