I'm looking for a word that has the same meaning as "plagiarism" but in relation to plagiarized ideas only, i.e. not related to writing, art work, drawing etc.
I don't believe there exists such a word, to describe someone who steals ideas, as it cannot be classified as a crime unlike plagiarism, which also functions as a verb.
I can think of only one expression: to take credit
Scenario: A tells B an idea on how to improve the company's productivity tenfold. Then B, behind A's back, goes to their boss and suggests the very same idea. The idea proves to be a success but it is B who takes the credit.
To steal: To present or use (someone else's words or ideas) as one's own.
To take the credit: to allow people to believe that one has done something praiseworthy, whether or not one has actually done it
I found this link about how "stealing" ideas in the business world can be perfectly legal but there are exceptions to the rule. http://yourbusiness.azcentral.com/legal-term-stealing-business-idea-12733.html
- Copyright Infringement
- Trademark Infringement
- Patent Infringement
- Tortious Interference
Intellectual property would generally cover the notion of a 'protected' or 'owned' idea, in a strictly formal sense (patents on inventions, mechanical/chemical processes, innovative and unique ideas (such as the rules and mechanics used in the trading card game Magic: The Gathering, which other TCG's are prohibited from using), software, copyrighted creative works (such as the Star Wars or LOTR universes, which must be licensed to be included and expanded in other media, such as books or video games), etc.
In this case, you could use intellectual property theft, which is a term used by the FBI.
For an informal notion, as in 'borrowing an idea used conceived of by someone else', I can't think such word to describe this other than appropriation (if the idea is not credited or attributed to it's originator), since an idea is immaterial and as such cannot be 'owned' the same way a material object, such as a publication or written text can be.