Untrustworthier

Only if they begin with un- are they likely to end in -er, as in ‘untrustworthier’.

Source: wiktionary

In the May 1995 Word Ways, Darryl Francis gave examples of words having every numerical score from 1 (a) to 248 (superstitiously), and challenged readers to come up with a word scoring 249. Leonard Gordon suggested pyknodysostotics, pericardiomediastinitis, electroencephalographers, hexanitrodiphenylamine, hyperprothrombinaemia, photoroentgenographic, mercaptobenzothiazole and chemopallidothalamectomy, all but the first and last in Webster's Second or Third or inferrable from it. Richard Sabey noted superinstitution in Webster's Second. Susan Thorpe added inauthoritativeness, reconstructiveness and photosynthesizing from the OED. Sir Jeremy Morse suggested zoophysiologists (inferred from the Funk & Wagnalls unabridged word zoophysiology) and the inferred word untrustworthier.

Source: wiktionary

Who is sneakier, untrustworthier, and all round more devious that the newest oxymoron, the "Clinton Justice Department"?

Source: wiktionary

On the day he wrote it William was in ‘a low, desponding, and queer state’. ‘I can’t describe my feelings,’ he said, but he had suicide in mind. The sharp instrument was ready for that purpose. ‘I did feel certain that the Devil would come to me that night’, he recalled, but there was no untrustworthier master than the Devil, and he failed to appear and claim his soul.

Source: wiktionary