The -er nominalizations as nominal components of complex predicates in sentences with human subjects sometimes denote a feature of the sentence subject:
She is a liar. = She often lies.
An adjectival modification of the nominalization then expresses the manner or the extent to which the subject has the given feature:
She is a clever liar. = She lies in a clever way.
This type of adjectival modification gets the
functor MANN.
For more details on nominalizations and on functors given to their modifications see Section 10, “Nominalizations”.