use '?' for JOKER (blank)

From letters X, E, N, O, T, R, O, P, I, C  I made following words

10 letter words

xenotropic[21]

9 letter words

exotropic[20], neotropic[13]

8 letter words

pecorino[12], entropic[12], inceptor[12], protonic[12]

7 letter words

princox[18], exciton[16], excitor[16], xerotic[16], porcine[11], porcino[11], entopic[11], nepotic[11], portico[11], coontie[9], cointer[9], noticer[9], coronet[9], pointer[9], protein[9], tropine[9], portion[9]

6 letter words

exonic[15], poxier[15], exotic[15], cortex[15], export[15], toxine[13], pincer[10], prince[10], copier[10], crepon[10], cooper[10], incept[10], pectin[10], poetic[10], octopi[10], tricep[10], copter[10], tropic[10], coiner[8], orcein[8], recoin[8], orpine[8], pernio[8], operon[8], noetic[8], notice[8], cootie[8], pointe[8], option[8], potion[8], cretin[8], erotic[8], cornet[8], citron[8], cortin[8], cooter[8], octroi[8], croton[8], pterin[8], protei[8], tropin[8], pronto[8], proton[8], toonie[6], norite[6], orient[6], tonier[6], enroot[6]

5 letter words

xenic[14], xeric[14], toxic[14], toxin[12], oxter[12], copen[9], ponce[9], cripe[9], price[9], coper[9], optic[9], picot[9], topic[9], coopt[9], crept[9], opine[7], nicer[7], crone[7], recon[7], orcin[7], cooer[7], croon[7], repin[7], ripen[7], prone[7], orpin[7], prion[7], poori[7], porno[7], cento[7], conte[7], oncet[7], ontic[7], tonic[7], conto[7], inept[7], netop[7], pinot[7], pinto[7], piton[7], point[7], topoi[7], citer[7], recit[7], recti[7], trice[7], recto[7], toric[7], tripe[7], print[7], repot[7], toper[7], trope[7], troop[7], irone[5], oorie[5], inert[5], inter[5], niter[5], nitre[5], trine[5], noter[5], tenor[5], toner[5], trone[5], intro[5], nitro[5]

4 letter words

epic[8], pice[8], cope[8], coop[8], poco[8], crop[8], cine[6], nice[6], cone[6], once[6], cion[6], coin[6], coni[6], icon[6], coon[6], pein[6], pine[6], nope[6], open[6], peon[6], pone[6], pion[6], poon[6], cire[6], rice[6], cero[6], core[6], coir[6], corn[6], peri[6], pier[6], ripe[6], pirn[6], pore[6], repo[6], rope[6], porn[6], poor[6], cite[6], etic[6], cent[6], cote[6], otic[6], coot[6], pent[6], pint[6], poet[6], tope[6], topi[6], rein[4], inro[4], iron[4], noir[4], nori[4], nite[4], tine[4], note[4], tone[4], into[4], onto[4], toon[4]