One’s true motive or identity, unseen by others; see “clothing”
When we dream of underclothes – whether our own or other people’s – we are considering hidden attitudes to self-image or sexuality.
A Guide to Dreams and Sleep Experiences
If black: restraint or unconscious sex drives. Dirty or grubby: sex attitudes we are not proud of; difficult feelings about biological side of self. ... A Guide to Dreams and Sleep Experiences