1. [adj]  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"
2. [adj]  thin and weak; "a wispy little fellow with small hands and feet"- Edmund Wilson

WISPY is a 5 letter word that starts with W.