netts
The word is deflects; the missing letters are Fand C.
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 26 words with the pattern D--TS. That is, five letter words with 1st letter D and 4th letter T and 5th letter S. In alphabetical order, they are: dalts dants darts dauts dawts debts deets delts dents dicts diets dints dirts ditts doats doits dolts dorts douts dowts drats ducts duets duits dunts dusts
tattle, totter, tatter, titter, tatted, tattoo, totted, tutted
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 1 words with the pattern DY---TS. That is, seven letter words with 1st letter D and 2nd letter Y and 6th letter T and 7th letter S. In alphabetical order, they are: dynasts
faults
netts
There is no such word as "petitition" but there is a word "petition". Count the Ts--there should be only two.
Ts
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 1 words with the pattern U--TS. That is, five letter words with 1st letter U and 4th letter T and 5th letter S. In alphabetical order, they are: units
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 1 words with the pattern -V-TS. That is, five letter words with 2nd letter V and 4th letter T and 5th letter S. In alphabetical order, they are: evets
tattle
Gibberish.
Ts
Ants
An eight-letter word cannot be made from four letters. T, I, E and S are not sufficient to make an eight-letter word without knowing what letters can be repeated and how often they are repeated. TESTIEST could work if you allow three Ts.
There can be some confusion as Russian has a letter С, which is analogous to the Latin (and English) S. It is always pronounced as "s". It also has the letter Ц, which is analogous to the Latin (though not the English) C. This letter is pronounced as "ts". с = 's' as in see ц = 'ts' as in cats