sporophyll or sporophyl/ʹspawrəfil, ʹspo-/ noun

• unsentimental
• unserviceable
• unsettle
• unsettled
• unsex
• unshackle
• unshakable
• unshaven
• unsheathe
• unship
• unsighted
• unsightly
• unsinkable
• unskilful
• unskilled
• unskillful
• unsling
• unsnap
• unsociable
• unsocial
• unsolicited
• unsophisticated
• unsound
• unsparing
• unspeakable