“map of days outworn”
'Days outworn' means the past ages, the worn-out days of long ago. The poet calls the youth's face a 'map' — a chart containing all the information of a larger territory — of that earlier world when beauty was genuine and unadorned. His face is a surviving record of what true beauty looked like before cosmetics and wigs corrupted it.
“bastard signs of fair were born”
'Bastard' means illegitimate — not born of genuine parentage. 'Signs of fair' are outward displays of beauty. Together, 'bastard signs of fair' denotes counterfeit or artificial beauty — cosmetics and wigs that mimic natural looks without being natural. These devices 'durst inhabit on a living brow' means they dared to take up residence on a person's face.
- TLN 943historical topical
“golden tresses of the dead, The right of sepulchres, were shorn away, To live a second life on second head”
The poet objects to the Elizabethan trade in wigs made from hair cut from corpses. 'The right of sepulchres' means what belongs by right to the tomb — the hair of the dead. 'Shorn away' means shaved off before burial and sold so the dead person's hair could 'live a second life on second head' as a wig on someone else. The practice is treated as a desecration of the dead.
“him as for a map doth Nature store, To show false Art what beauty was of yore”
The closing couplet completes the sonnet's argument. Nature preserves the youth as a living demonstration — a map — to expose what 'false Art' (artificial cosmetics, wigs, and cosmetic craft) can only counterfeit. 'Of yore' means of old, in former times. The couplet turns the youth from a private beloved into a public standard: he is what beauty used to be before the world's corruption, and Nature keeps him on display to shame the imitators.
historical The sonnet form