They are taller than humans, at a species average of around 7 feet(ish), making them the largest race by some margin.
Orcs (of both sexes) are strongly built (in proportion to their height), and have fine hair similar to humans'. There is not more than a foot or so height variation between fully-grown orcs. Noses tend to be flat. Their ears are rounded and may or may not have lobes.
Their skin has a blueish-greenish-grey tint (which does not vary much with area of origin, unlike most of the other races). Hair ranges from light browns to dark. Eyes are anything from orange to brown, hazel or blue or grey.
If we're around Twine Wars time, orcs are the stupidest of the races - it's partly to do with a lack of understanding between species, but orcs think slowly and don't tend to remember details well.
Personalitywise, the stereotypical orc is quiet and, despite being slow, given to moments of introspective thoughtfulness. They are not more aggressive or given to 'berserker'dom than other races, although physically very capable indeed with training. They can be quite soulful and a little vulnerable - or, then again, may be rebelliously thick-skinned, idealistic, ambitious and wilful. (Females tend to the former and males the latter, but it's very often the other way around, too.)
In artificial settings such as mixed-species armies, rocca are often quiet, even insecure, except when drunk. Which is often. Somewhat surprisingly, even when drunk, they're less likely to be foul-mouthed than anyone except perhaps trolls.
Academically, orcs tend to be all-rounders. Some orcs have a talent for mechanics or physics. Many never specialise. (The academic system provides equally well for specialists and generalists.) The stereotype is that they are loyal and somewhat unquestioning followers: a generalisation that is not terribly accurate. Orcs have made great leaders, with a tendency to be what, for lack of a better term, has been described as noble.
(By 'Future Shade' timeline the "orcs are least intelligent" thing is LONG since out of date.)
Orcs have a naturally high alcohol tolerance (in marked contrast to goblins!), and tend to be heavy drinkers. An orcish drunk will usually follow the rule of "the quieter they are, the louder they brawl"; a minority just get very sleepy and tractable.
All orcs get seasick. Some can overcome this with practice, though many prefer not to. Owing to a unique feature of their hearing, they love bass frequencies.
Orcs have very sensitive noses when it comes to 'organic' smells: people, food or plant matter. (Their sense of smell as applied to 'inorganic' smells - chemicals and metals - is only average.)
Orcs are unlikely to have magical ability: in the interracial statistics, they beat only trolls. This isn't to say that an orcish magician is particularly rare or noteworthy. Telepathy is not common, with the incidence only a little higher than in elves.