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

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