they admitted the force of my argument but remained dubious.
Examples of dubious
dubious
His looks, too, render dubious the desperate envy that defines the young Ripley.
From the theatlantic.com
Some of the tiger mum's dubious parenting approaches are just plain child abuse.
From the independent.co.uk
The last three have at least some, although still dubious, experimental support.
From the guardian.co.uk
Avalon Harbor Beach on Catalina won the dubious honor of topping those rankings.
From the ocregister.com
Pitcher Jeff Francis edges out shortstop Troy Tulowitzki for this dubious award.
From the denverpost.com
According to an admittedly dubious online source, her spirit animal is the hawk.
From the latimes.com
Las Vegas has the dubious distinction of being America's unhappiest large metro.
From the theatlantic.com
That sounds like a dubious idea to me, so feel free to suggest something better.
From the theatlantic.com
Bill Loeffler came within one stroke of some kind of dubious achievement Sunday.
From the denverpost.com
More examples
Doubtful: fraught with uncertainty or doubt; "they were doubtful that the cord would hold"; "it was doubtful whether she would be admitted"; "dubious about agreeing to go"
Doubtful: open to doubt or suspicion; "the candidate's doubtful past"; "he has a dubious record indeed"; "what one found uncertain the other found dubious or downright false"; "it was more than dubitable whether the friend was as influential as she thought"- Karen Horney
Not convinced; "they admitted the force of my argument but remained dubious"
(dubiously) questionably: in a questionable and dubious manner; "these were estates his father questionably acquired"
(dubiousness) doubt: the state of being unsure of something
Doubt, a status between belief and , involves uncertainty or distrust or lack of sureness of an alleged fact, an action, a motive, or a decision. ...
Arousing doubt; questionable; open to suspicion; In disbelief; wavering, uncertain, or hesitating in opinion; inclined to doubt; undecided
(dubiously) in a dubious manner; accompanied by doubt
(dubiosity) The state or characteristic of being dubious