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
unclear not clear to the mind; "the law itself was unclear on that point"; "the reason for their actions is unclear to this day"
vague -
not precisely limited, determined, or distinguished; "an undefined term"; "undefined authority"; "some undefined sense of excitement"; "vague feelings of sadness"; "a vague uneasiness"
defined clearly characterized or delimited; "lost in a maze of words both defined and undefined"; "each child has clearly defined duties"
indefinite not decided or not known; "were indefinite about their plans"; "plans are indefinite"
vague -
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"
indistinct not clearly defined or easy to perceive or understand; "indistinct shapes in the gloom"; "an indistinct memory"; "only indistinct notions of what to do"