Perhaps you should try some spelling variations:
"heir apparent" » "huir apparent", "her apparent", "hair apparent", "heir aparente", "heir apaparente", "heir apparental"
"heir apparently" » "huir apparently", "her apparently", "hair apparently", "heir aparentely", "heir apaparentely", "heir apparentally"
"heir parent" » "huir parent", "her parent", "hair parent", "heir aparente", "heir parental"
"weir apparent" » "weir aparente", "weis apparent", "wei apparent", "weil apparent", "weir apaparente", "weir apparental"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((((("heir apparent") OR ("weir apparent"))) OR ("heir apparently"))) OR ("heir parent"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((((\"heir apparent\") OR (\"weir apparent\"))) OR (\"heir apparently\"))) OR (\"heir parent\"))".
• Removing quotes may allow a broader search: (((((( heir apparent ) OR ( weir apparent ))) OR ( heir apparently ))) OR ( heir parent )).
• Adding a wildcard symbol may retrieve word variants: (((((("heir apparent") OR ("weir apparent"))) OR ("heir apparently"))) OR ("heir parent"))*.