Clue: Unpretentious headdress with a hint of severity for wife (6)
Answer: SIMPLE
Explanation: Unpretentious headdress with a hint of severity for wife (6)
(w)(**S**)**IMPLE** ("headdress" (WIMPLE) *with* [*a hint of*] S(everity) *for* (i.e. replacing) W(wife)