The word "tattletale" contains the letter T three times.
Remember
That's an unusual question.
Giggle, gaggle, legging
Taramasalata
Cachectic
Ore is a three letter word and is a mineral that contains metal that is valuable enough to be mined.
deeded - to be given the deeds to somewhere/something
succubus
The word "deeded" contains only 2 letters that are each used three times within the word. It is the only such word in the English language.
good times=fun
Inimical comes to mind, but I'm sure there are others. I can do you one letter better: a 7 letter word that contains three Is is "idiotic".