An object other than clothing that actually, physically allows some amount of light to pass through it. If a normally opaque object such as a wooden desk is rendered partly invisible by artistic fiat, that's x-ray.
If some article of clothing is transparent, use see-through clothes instead. If a person seems to be disappearing, fading may be appropriate as well; for a character's skin that's transparent, see see-through body.
The following tags are aliased to this tag: transparency (learn more).
The following tags implicate this tag: transparent_umbrella (learn more).