The simple definition of deceptively is in a deceptive way, but in actual use the adverb is often ambiguous, sometimes meaning in reality but not in appearance and sometimes in appearance but not in reality. Because of the potential confusion, deceptively might be best avoided where its meaning isn’t clear.
For example, if I were to say, “The cat is deceptively friendly,” it could mean either (1) that the cat seems unfriendly but is actually friendly, (2) that the cat seems friendly but is actually unfriendly, or (3) that the cat is friendly in some undescribed deceptive way. So, depending on context and reader interpretation, deceptively has multiple conflicting meanings
But the word is unquestionable when used to mean, literally, in a deceptive way—as in, “The deceptively edited video portrayed the crook as a philanthropist.”
Let’s look at some examples of deceptively used in opposing ways. These writers use deceptively to mean in appearance but not in reality (like the cat that seems friendly but is actually unfriendly):
It’s no mystery why images of shocking, unremitting violence spring to mind when one hears the deceptively simple term, “D-Day.” [Life]
The French are certainly fond of Allen, who opened the Cannes Film Festival with this deceptively light, offhandedly profound comedy. [Boulder Weekly]
And in these examples, deceptively means in reality but not in appearance (like the cat that seems unfriendly but is actually friendly):
This breezy but deceptively plot-packed little novel starts and ends placidly in small-town Nebraska. [St. Louis Post-Dispatch]
Beneath the big man’s jolly exterior was a deceptively insecure guy who cared a lot about his legacy. [NESN]
And sometimes, as readers, we just can’t tell what the author means by deceptively—for example:
Hillis is a versatile offensive player and a deceptively good athlete. [Sporting News]
If he is a deceptively good athlete, does that mean he is actually bad? Or does he just seem like a bad athlete? And if so, why is he in the NFL?
She’s a visual artist and writer whose work combines photographs, text, and deceptively simple paintings. [The Millions]
Are the paintings simple in appearance but complicated in subtext, or are they complex in appearance but simple in subtext?
To be fair, we should point out that some instances of deceptively are made perfectly clear by context—for example:
Yet, the hollow interior of the wood means that the bike is deceptively light. [Forbes]
From this we can infer that the bike looks heavy but is actually light because of its hollow interior.