That means you can't ever produce a search with zero matches. For example, when you're searching for all emails containing a particular word, InfoClick would show the completions "connection", "connexion", and (the misspelled) "connecsion", if you'd actually used those words in your emails.
InfoClick offers additional features to make searching your emails easier. To see all emails received from educational organizations in the US, simply type .edu in the From field. With a single click, you can narrow-down your search to only those emails that had an attachment, and/or those received in a given date range, and/or those that contain specific words. You can choose, as alternatives, all displayed word spellings used in the emails, so you don't miss an email because of spelling errors.
InfoClick also offers a note editor, allowing you to collect and organize links to emails, files, Web pages, and other URLs (notes are completely searchable).

Compatibility: macOS 10.10 or later 64-bit
Homepage: https://nisus.com