Definition of "dubious"

There are several reasons why the line's future is now dubious. With the exception of Horsmonden, the stations are most inconveniently sited. This is largely because the Wealden villages were built on ridges, and in fact most Wealden stations are badly placed.

1960 March, H. P. White, “The Hawkhurst branch of the Southern Region”, in Trains Illustrated, page 173

Evasive, womanising, boastful, malicious, untrustworthy, an inveterate gambler who combined his mediocre military career with running a high-class brothel, permanently cash strapped and viciously quarrelsome, his character is as dubious as his unsavoury appearance.

2011 February, Nigel Jones, “A Tale of Two Scandals”, in History Today, volume 61, number 2, pages 10–17

Urban Dictionary records at least 66 of the terms found by the present research, but as this dictionary liberally accepts words, definitions, and sample sentences based solely on the say-so of contributors, in the absence of corroboration from other sources the authenticity of some entries must remain dubious.

2018, James Lambert, “A multitude of ‘lishes’: The nomenclature of hybridity”, in English World-Wide‎, page 2

Last year, President Obama had large majorities in Congress and hopes of passing a comprehensive climate and energy bill. Next year, he faces a new Congress much more dubious about the reality of climate change and considerably more hostile to international efforts to deal with it.

2010, John M. Broder, "Global Climate-Change Talks Begin in Cancun With More Modest Expectations", New York Times, November 30, Section A, Column 0, Foreign Desk, page 12