Nouns

(n)speciala special offering (usually temporary and at a reduced price) that is featured in advertising“they are having a special on pork chops”
(n)speciala dish or meal given prominence in e.g. a restaurant
(n)speciala television production that features a particular person or work or topic“the last of a series of BBC specials on Iran is being shown tonight”

Adjectives

(s)particular, peculiar, specialunique or specific to a person or thing or category“the particular demands of the job”, “has a particular preference for Chinese art”, “a peculiar bond of sympathy between them”, “an expression peculiar to Canadians”, “rights peculiar to the rich”, “the special features of a computer”, “my own special chair”
(s)specialfor a special service or occasion“a special correspondent”, “a special adviser to the committee”, “had to get special permission for the event”
(s)especial, exceptional, particular, specialsurpassing what is common or usual or expected“he paid especial attention to her”, “exceptional kindness”, “a matter of particular and unusual importance”, “a special occasion”, “a special reason to confide in her”, “what's so special about the year 2000?”
(s)specialadapted to or reserved for a particular purpose“a special kind of paint”, “a special medication for arthritis”
(s)limited, specialhaving a specific function or scope“a special (or specific) role in the mission”
(s)particular, specialfirst and most important“his special interest is music”, “she gets special (or particular) satisfaction from her volunteer work”
(s)extra, specialadded to a regular schedule“a special holiday flight”, “put on special buses for the big game”