A word or phrase is ambiguous if in the mind of a hearer or
reader it has two or more quite different meanings and the interpreter is
uncertain as to which was really meant. In argument such a situation would
at all times be undesirable.
Joe says, 'Henry likes pudding better than his wife.' And one or
more people hearing him are left wondering Whether Henry likes pudding
better than he likes his wife or if Henry likes pudding more than his wife
does.