scintilla
noun
there is not the faintest scintilla of truth in it:
particle, iota, jot, whit, atom, speck, bit, trace, ounce, shred, crumb, morsel, fragment, grain, drop, spot, mite, tittle, jot or tittle, modicum, hint, touch, suggestion, whisper, suspicion;
informal smidgen, smidge, tad;
Irish, informal stim;
archaic scantling, scruple.
scintilla Oxford Dictionary of English