Noun: An opinion held by a man.
Verb: An opinion expressed by one who is a man.
Adverb: To express a manpinion that ends in 'ily' or 'ly'.
In his manpinion, when doing 1970s sexual role playing Doug liked his wife to wear cutoffs instead of disco hot pants.
In his manpinion, Mr. Austin Smith felt turn signals were an unnecessary part of expressway merging.