Here's what rhymes with fascinatingly.
hesitatingly gratingly irritatingly aggravatingly nauseatingly devastatingly exasperatingly illuminatingly accommodatingly titillatingly unhesitatingly deprecatingly penetratingly calculatingly humiliatingly invigoratingly infuriatingly ingratiatingly intimidatingly excruciatingly Words that almost rhyme with fascinatingly
ragingly engagingly amazingly unfailingly animatedly basically scathingly unavailingly rakishly creatively evasively pervasively imitatively abrasively piratically jadedly qualitatively authoritatively persuasively meditatively exaggeratedly entertainingly exasperatedly lackadaisically algebraically appreciatively collaboratively prosaically uncomplainingly complicatedly legislatively manipulatively administratively