A wolf usually arrives in a poem with teeth. In "the wolf" it arrives with a definition. "The wolf is a concept," the speaker says, and says it again three lines later, as if the first attempt hadn't quite settled the matter. The animal never appears. What the poem describes is a kind of deception: someone who seems different from you "in someway, shape or form" but isn't, someone who is "lying," "pretending," and "not being true." The wolf here is a mask, and the poem is mostly about the person wearing it.
The reasoning is worth following closely, because the poem builds its idea by correcting itself. It starts with a denial: "Its not like someone is a wolf." Then it replaces that with a comparison: "Its like someone is pretending to be a wolf." The phrase "Its like" comes back a third time when the speaker tries to describe the difference between you and the other person, so the poem keeps circling through approximations instead of arriving at one clean image. There is a pleasing oddity in the logic too. We expect a wolf to be the real danger, the predator in disguise, as in the old saying about a wolf in sheep's clothing. This speaker turns that around. The person is only pretending to be the wolf, so the threat is the performance, not the predator. It is left open whether the pretender fakes being dangerous, fakes being distant, or fakes being "different" in some other way, and that openness lets the idea stretch to fit almost any betrayal a reader has in mind.
Structurally, the poem is stripped down. It is free verse with no rhyme and almost no punctuation, and the lines run short and plain, close to speech. The missing apostrophes in "Its" and the slip in "their not" give it the feel of something typed quickly and honestly, whether or not that was the intention. The repeated line "The wolf is a concept" works like a refrain, and it frames the first half of the poem like a pair of brackets. After "But their not," the poem breaks into single-word and near-single-word lines: "They are lying / Pretending / Not being true." These three do not move the thought forward. They restate it in slightly different words, like someone pressing the same bruise to check it still hurts. The flatness of "Not being true" is part of the effect, since the speaker seems to run out of fancy language exactly where the feeling is strongest.
The word choices carry the tone. "Concept" is cold and abstract, the vocabulary of a classroom, and it sits oddly against the hurt underneath. Calling the wolf a concept keeps it at arm's length, which is perhaps how someone talks when they are trying to be analytical about a wound. The last line shifts into theatre: "They put up an act just to fool you." "Act" turns the deceiver into a performer, and "just" shrinks the motive to something petty, even insulting. That line is also the first time the poem fully turns toward "you." Until then the speaker has been explaining, and by the end is accusing.
The heading attached to the poem, "I Threw the Supermarket Flowers From the Windowsill," adds a concrete picture that the body of the poem never gives. Judging by the imagery, supermarket flowers are a cheap, ready-made gesture of affection, bought quickly and meant to look like care, and throwing them out is a rejection of something that only resembled sincerity. That is an inference, but it fits the poem's theme neatly: a bunch of flowers can be an act, just as the wolf is.
What makes "the wolf" worth reading is how openly it shows a mind working through an experience. It does not dress its feelings up in elaborate metaphor. It takes a familiar animal, strips away the fur and fangs, and leaves the idea underneath, that the most unsettling thing about a person can be the distance between who they appear to be and who they are. The poem's plainness is a strength as well as a limit. A reader can see exactly how the speaker is trying to make sense of being fooled, and that is a very recognisable thing to do.