petit four/ʹfaw/ (French /pəti fur)/ noun (pl petits fours petit fours /ˌpeti ʹfawz/ (French /fur)/)

• unbounded
• unbowed
• unbranded
• unbreakable
• unbridgeable
• unbridled
• unbroken
• unbuckle
• unbundle
• unburden
• unbutton
• uncalled-for
• uncanny
• uncap
• uncapped
• uncared-for
• uncaring
• unceasing
• unceremonious
• uncertain
• uncertainty
• uncertainty principle
• unchangeable
• unchanging
• uncharacteristic