That would be "ciTy". It has a T as the third letter and is the opposite of country.
Four letter words with X as the third letter:boxyfoxyluxenextpoxysexytaxitextwaxy
stop or halt is a four letter word meaning the opposite of go.
Some four letter words with O as the third letter are:aloeanonatomblobblotblowbookboomboonboorbootbrowbuoychopchowclodclogclotcloycookcoolcropdoomdoordropflogflopflowfoodfoolfootfrogfromglowgoodgoofgrowhoodhoofhookhoopiconidolironknobknotknowlionlookloomloonmeowmoodmoonmoormootneonnookoboeplodplotplowploypoofpoohpoolpoorprompropprowroofroomrookrootscowshodshopshotshowslopsmogsnobsoonsootspotstopthoutooktoottrodtrotuponwhoawhomwoodwoofwoolzoom
Some examples of four-letter words that have the third letter "i" are "spin," "mild," "sink," and "pink." The third letter in these words is the letter "i," which falls in the third position of the word. These words follow a specific pattern of letter placement, making them distinct from other four-letter words.
into
A four letter word and the opposite of fat would be thin.
left is a four-letter word
gain.
Skin
rare
they
fire