over-optimistic 
adjective
Unjustifiably optimistic: I feel she is being rather over-optimistic...
- Many social workers are often over-optimistic, and perhaps they sometimes allow that process of rehabilitation to take longer than it should.
- We predicted last quarter that the region's retailers may well issue further warnings in 2004 with some companies' over-optimistic expectations of the Christmas season coming home to roost.
- Film-makers have been experimenting with 3 - D since 1903 and there has been a succession of over-optimistic claims that it is about to become a mainstream technology.
Derivatives
over-optimism
- Either through over-optimism or inertia, UK corporate pensions are still hugely exposed to equities - still as high as 64% on average at the end of 2002.
- Maybe there was a sense of over-optimism after finishing fourth in the league last year.
- And no, this isn't a case of over-optimism following Caley Thistle's 3-1 victory over Celtic this year.
over-optimistically
- Now, perhaps over-optimistically, she hopes that I'm a Celebrity… will be her relaunch pad back into the public eye: ‘There's a TV show that I want to present and I need to raise my profile in order to do it.’
- When life insurance companies became more competitive, they began buying up estate agents and over-optimistically projecting policies to offer the cheapest premiums.
- On the other hand the private purchase in 1846 of Philip IV Hunting Wild Boar, over-optimistically attributed to Velázquez, for £2,200, provoked howls of protest.