This paper examines reprise questions: questions which request clarification of the meaning intended by a speaker when uttering a word or phrase. As such they can act as semantic probes, providing information about what meaning can be associated with word and phrase types. We present corpus evidence regarding the meaning of nouns and noun phrases, and argue that this evidence runs contrary to the usual treatments of semantics in HPSG, and to the traditional generalised quantifier view of NPs as sets of sets. Instead we outline an analysis of NPs as (possibly functional) sets of individuals.