pontoon
There are 1 Cs, 1 S, 2 Ns, and 3 Ts for a total of 7 consonants in the word, 'Constitution'.
another
dodders, daddies
bikini, minimi, illicit, idiotic -- Here is a full list of them: wordunscrambler.net/word-list/7-letter-words-with-3-is
Oxblood is a 7 letter word with 3 o's. It is a color. It is a dark shade of red that resembles burgundy.
success
consonants...
petting zoo
The word Mollusk is a 7 letter word.
To my mind right now, there is no word of your request.
three (3) letter word: Utu. ulu. four (4) letter word: unau. Urdu. seven (7) letter word: umbundu.