Cooze: A cooze is a superficial, shallow, provincial, and generally ignorant person, who is so intellectually and socially repulsive.

Source: http://www.urbandictionary.com/define.php?term=cooze

“Rat mails the letter. He waits two months. The dumb cooze never writes back.” from The Things they Carried by Tim O’ Brien

The word cooze is a word that describes a all the features of a coward in which Rat is calling Curt Lemon for fooling around with the smoke grenade.