With denotation meaning the literal definition of the word, the title of Saki's story indicates more than one person or thing that intrudes into a region without proper license.
Now, as far as the story itself is concerned, initially interlopers is identified as the two main characters, Ulrich von Gradwitz and Georg Znaeym, as well as the men of each of the hunters. In the brief moment after von Gradwitz is startled by the sudden encounter with his enemy as he comes around the trunk of a huge beech tree, the two men stare at each other without doing anything. For,
a man who has been brought up under the code of a civilisation cannot easily nerve himself to shoot down his neighbour in cold blood and without word spoken except for an offense against his hearth and honour.
So, they hesitate to fire at each other because of the the interloper, their civilised natures. Then, before the act of
hesitation had given way to action, a deed of Nature's own violence overwhelmed them both
and the "pestilential wind" causes the old tree crashes upon them and they are pinned beneath them. Thus, the wind, too, becomes an interloper that prevents the men's firing of their rifles. As they lie there between life and death, Ulrich decides that their enemity is not of the importance he has believed; in this change of heart, he offers to reconcile with his enemy and become friends with him in the forest:
And if we choose to make peace among our people there is none other to interfere, no interlopers from outside....
Of course, the situational irony of his word interloper which Ulrich has meant to denote other people is not apparent to either man until the last line of the story: "Wolves." They are the penultimate interlopers; they are the consummate interlopers, for they intrude into the field of forgiveness and friendship, giving the word interlopers the most significant denotation.