The word centesimos is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 17
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (31 words)
cements, cenotes, cession, coesite, consist, cosiest, cosines, emetics, entices, incests, incomes, insects, meioses, miocene, mitoses, moisten, nemesis, nosiest, notices, octenes, oecists, onetime, section, seitens, sestine, siemens, sitcoms, somites, stenose, stomies, tocsins