An english term meaning that something doesn't meet the expectations set in it or is less good than a similar thing coming before or after it. It is commonly used in the media and sometimes written like this: less-than-stellar.
Those sales figures are less than stellar.
Godzilla 2000 was a less-than-stellar movie, and Dean Devlin's acting was less than stellar too.
Example from knifegirl's w/u on Falco:
Falco's third album, Falco 3, contained the single Rock Me Amadeus, which reached the top of those charts that measure such things in the U.S., Germany, Austria, and England. ... A few less-than-stellar albums followed,...
substandard; dissatisfactory, half assed