Most "free key" websites are fronts for malware. Downloading a crack can lead to ransomware or identity theft.
At face value, the phrase suggests obtaining a valid for Portraiture (by Imagenomic) without paying. In practice, search results and forums (Reddit, torrent sites, “crack” blogs) lead to: license key portraiture 4 free
I understand you're looking for an in-depth analysis of the phrase — likely in the context of software like Portraiture (a popular Photoshop/Lightroom plugin for skin retouching). Most "free key" websites are fronts for malware