The expletive is an insight into the 2008 world champion's delicate negotiations with the British team, but Hamilton ruled out letting the impasse become a "sabbatical".
"There are lots of sticking points," the 27-year-old said at Spa, where the 2013 'silly season' has shifted into a higher gear.
"You never just sign the first contract that's given to you because most of the time it's sh*t," he is quoted by the Sun.
"Nothing's signed, nothing's decided."
Although his alternatives appear limited, Hamilton is not ruling out a switch to a rival team.
"You don't know what is going to happen because in 2014 the regulations change quite heavily. So you don't know what is going to be the (right) place," he said.
The Times' Kevin Eason said that comment could tie in with speculation McLaren is happy to increase Hamilton's pay, but the team wants him to sign a long-term deal.
Hamilton ruled out letting the impasse result in him being left with no seat in 2013.
"I'm not going to walk away from F1. Plus, why would I take a sabbatical? I am too young. That is definitely not going to happen," he said.