zippyadj (zippier, zippiest)

• unskillful
• unsling
• unsnap
• unsociable
• unsocial
• unsolicited
• unsophisticated
• unsound
• unsparing
• unspeakable
• unspecified
• unspoiled
• unspoilt
• unspoken
• unstable
• unsteady
• unstep
• unstick
• unstinting
• unstop
• unstoppable
• unstressed
• unstring
• unstructured
• unstrung