vague

not clearly understood or expressed

• “an obscure turn of phrase”
• “an impulse to go off and fight certain obscure battles of his own spirit” Anatole Broyard
• “their descriptions of human behavior become vague, dull, and unclear” P.A.Sorokin
• “vague...forms of speech...have so long passed for mysteries of science” John Locke

not precisely limited, determined, or distinguished

• “an undefined term”
• “undefined authority”
• “some undefined sense of excitement”
• “vague feelings of sadness”
• “a vague uneasiness”

lacking clarity or distinctness

• “a dim figure in the distance”
• “only a faint recollection”
• “shadowy figures in the gloom”
• “saw a vague outline of a building through the fog”
• “a few wispy memories of childhood”