Answer: rarefy

AnswerCrossword Clue
RAREFYRefine
rarefyto make or become thin, as air
rarefyto make less dense, also RARIFY
RAREFYReduce the density of
RAREFYMake more subtle
RAREFYLessen the density of
RAREFYBecome thinner, as air
RAREFYMake more refined
RAREFYThin beam broken by person in stripes (6)
RAREFYRefine further
RAREFYMake thin or porous
RAREFYMake less dense
RAREFYBecome less dense
RAREFYAttenuate
RAREFYMake less dense.
RAREFYMake purer.
RAREFYMake thin or less dense.
RAREFYAttenuate.
RAREFYBecome less dense.
RAREFYThin out
RAREFYBecome thinned