This study is devoted to the analysis of Italian idioms with either ordinary or support verbs (also called light verbs). The research focuses on the exhaustive description of idioms, and is based on their systematic classification according to the principles of the Lexicon-Grammar methodology developed by Maurice Gross (1975, 1979 and further). A thorough examination of the literature shows strong disagreement on the acceptability of some idiomatic constructions. For this reason, the Web was used as a corpus to verify judgments on the supposed ungrammatical constructions. This approach showed that idiomatic constructions which have always been considered ungrammatical are instead perfectly acceptable if contextualized. The results obtained include the following: passive is not a "special case" when it concerns idioms, and idiomatic constructions show the same complexity as non-idiomatic constructions.