Nudity: lack of clothing in any part of the body

Full nudity: lack of clothing across the entire body
Partial nudity: clothing in some parts, but lack of clothing in others

Barefoot: lack of footwear on feet

Bottomlessness: lack of clothing around waist

Toplessness: lack of clothing around torso

Young child (birth to puberty)

Infant (birth to first walking)

Toddler (first walks)

Adolescence (puberty to age of majority)

Young adult (18 to 40 years)

Middle age (40 to 60 years)

Old age (60 years till death)

All figures above are approximate. Definitions come from, but are slightly modified from, the Wikipedia articles of respective age groups.