Is 'intelligent money' or 'smart money' an economic term, and if yes, what does it refer to?
"Intelligent money" or "smart money" is not an economic term per se, but a finance term.
It is colloquially used in the finance industry to describe the collective group of individuals who are paid to actively manage funds, rather than passively manage funds. Active management differs from passive management in that the former chooses how to invest money based on individual perceptions of expected return, whereas the latter follows a predetermined simple rule, such as "buy equities in a weighting equal to their individual market valuations amongst the largest x stocks".
More generally, 'smart money' refers to the subset of active managers that act as if they possessed an informational advantage, and/or the ability to adapt a fund's investment strategy to market conditions. In this sense, smart money consists of hedge funds and stock-picking mutual funds and 'dumb money' consists of passive mutual funds. (Passive funds are more likely to be ETFs, though it's not mutually exclusive).
However few economists would consider investing with active managers to be the intelligent choice (given equal risk, passive investment outperforms active investment on average, net of fees).
Since the term is colloquial, it is hard to find an example which provides a definition. Notwithstanding this, the following article's title lines up with this explanation, and further, explains why "smart money" isn't ordinarily a smart place for money.
You may be seeing the same thing that I'm seeing (on social media), and I've added the links below as evidence of this, more often than not, they don't define what they mean (in this case, they do - for instance, you'll see "the smart money is moving against the USD" etc). This term is very common on social media stock discussions.
The way that I understand is that these are individuals who have a commercial interest in a position. For instance, if the price of oil goes through the roof and a company has a lot to gain from that, they may take a hedge out against the position, in case of a fall, especially if the price goes to an extreme and they know it can't be sustained (you'll see a massive short movement). This is true with currencies as well (ie: an export driven business must watch exchange rates). It should be of note that they aren't always the "smart" move and they generally are early to the party, as you can see with their bets against oil (very early, and notice how quickly they cut some of the shorts as prices plummeted). The key is to watch their positions; they will generally be short, but when they make a strong short position, that could spell that something will happen.
I do not think that this is an economic term; more of a trading term.
While it is typically hard to assess that something is not a term/thing, a google search for "intelligent money" only returned an investment company.