pellucid — allowing the maximum passage of light, as glass; translucent.
pure — free from anything of a different, inferior, or contaminating kind; free from extraneous matter: pure gold; pure water.
sheer — transparently thin; diaphanous, as some fabrics: sheer stockings.
thin — having relatively little extent from one surface or side to the opposite; not thick: thin ice.
translucent — permitting light to pass through but diffusing it so that persons, objects, etc., on the opposite side are not clearly visible: Frosted window glass is translucent but not transparent.
transparent — having the property of transmitting rays of light through its substance so that bodies situated beyond or behind can be distinctly seen.