Lol, no, but ‘modalities’ is a very common shibboleth for advance fee scams; others include:
United State Dollars
Dear Beneficiary
Dear Email Owner
Remain Blessed
But ‘modalities’ was the first single-word attribute that sprang to mind.
An email with ‘Receipt’ in the subject line from an unknown sender is something to be avoided.
I was going to say anything the shouts “non-native” English speaker, and that does quite well.
That one, in particular, shouts “From a country that uses English, just not my [US] country.”
ETA: also, “amazing,” when it should be amazingly. “Hope you are doing amazing,” or “Hope this finds you amazing.”
In a text or email?
Toll
Ifyouactrightnow
Yes I’m cheating the one word. But listening on TV, the announcer breathlessly combines them too.
Or anything that mentions Unpaid.
Yes, two votes for, “NOW!” They want to panic people into making rash decisions without thinking.
“Trump”
Guaranteed
Genuine
Legitimate
“Holistic” and “cleanse”.
Also “superfood”, “revolutionary”, “overnight” and “Gundry”.
If permitted to expand to two words, there’s “top doctor” and “root cause”.
My real name.
I have a few “black hole” email addresses where spam is either kept for a few minutes or deleted immediately, depending on my needs.
But anthing to my real firstname, instead of my “prefered” fake last-name, is spam.
I weave a complex web. I probably did not weave it all that well, but people who care know my phone number.
For me, the ONE word is the domain name. Whether it’s supposedly from the US Post Office who knows my email address but not my physical address, or from Amazon, or the federal government, a domain name that sounds different from these large visible entities is the first sorting test. Especially if it’s a domain outside the US.
Any email with RE or Re in the beginning of the subject line from someone I don’t know or the rest of a subject line I don’t recognize. Note that Re is short for ‘Reply’. One can’t begin a conversation with a reply; therefore, if you’re starting a conversation with a reply I know it’s bullshit. Those first two letters tell me it’s rightful place is in the Junk folder.
With the exception of emails from myself, that I mentioned in post #4 (from is first line), the first two letter of the subject line is pretty hard to beat in terms of how quickly one realizes it’s BS.
Government agencies, banks, etc. using Gmail/Hotmail/Outlook.
Somewhat confusingly, it’s also short for “regarding.”
Or “response”.
But specifically in email, “reply” is the official meaning. Such that for email systems, when you push the “reply” button to reply to an email message, the software automatically puts “Re:” in the front of the subject line.
In other circumstances, say a printed memo or a physical letter, “re:” might have other meanings, but in email it always means “reply”.
“Weird trick” OK, it’s 2 words, but still…
As mentioned above - use of gmail or yahoo or another bizarre email address from an “official” agency.
And again, not one word, but when I get emails confirming my “purchase” for some outrageous amount, giving me a toll-free number to call if I didn’t place the order. Yeah, scam city. Especially when it names PayPal, since I don’t have an account.
Right now I just checked my email because such things are frequent enough that I thought I could find an example, and sure enough I actually just got one! 
From “iCloud” which uses an email address with the “first-church. org” domain address. Because Apple would totally use such an address, right?
Here is the start of the email:
Hello XXXX@yahoo.com,
We’ve detected a recent login attempt on your App le account (XXXX@yahoo.com). As a precaution, we request that you confirm your account activity.
A few things… I love how they address me by my email address rather than my real name that Apple would know since it’s part of my account. Also, I do not have an iCloud account associated with Yahoo; my real account is an old mac.com account (it’s very old of course).
That space in the middle of the word “Apple” is interesting. You don’t see it in the message, but when I paste it in the post here it appears. I wonder if it’s an attempt to evade spam filtering systems by not having the real word “Apple” but using a character that doesn’t actually show up in an email. That’s a bit clever actually.
It’s two words but yeah “almost free” screams SCAM to me much more than just “free”. Back when I used to watch local evening news, there was a guy with a seamless vinyl siding company who offered to side the back of your house “almost for free” if you let them use the odd-sized leftovers. He threw so many qualifiers into the offer (nearly, almost, just like) that it was obvious that it would be nowhere close to free, and the back of your house would probably look like shit to boot!