In the poem "Hollow Men" by T.S. Eliot, what does the word "Shadow" mean in the context? http://www.blight.com/~sparkle/poems/hollow.html

I'll try my hand at answering this question, but I hope that others give it a shot as well.

I re-read the poem at the site that you gave, came up with my own interpretation of the Shadow, and then went looking for outside links only to find someone who answers the question better than I could. The link is given below.

Grover Smith writes:

With every effort to make the potential become actual a "Shadow" interferes. This, whatever its private value, has in the poem no clear conceptual reference. It implies Prufrockian inertia incapable of connecting imagination and reality, a defect of kinesis, in part a volitional weakness and in part an external constraint. Deathlike, it hinders even the attempt at prayer through which the speaker might come into the "Kingdom" of pure actuality beyond. Eliot's threefold grouping of contrasts between prospect and fulfilment comprehends three failures. The oppositions of potentiality and actuality are not the Aristotelian or Thomistic ones; they blur as the enumeration passes from "potency" and "existence" to "essence" and "descent," but each constitutes an antithesis compatible with Aristotelian dialectic. Even "motion," normally actual, can fit into the potential category through its special meaning of "initial impulse," by which it contrasts with "act:" Each of the three groups (by ambiguities) recapitulates the preceding, until by accumulation all three groups combine in the third, just as, according to Aristotle, the soul includes in its highest powers those of the inferior species. Perhaps the first group chiefly connotes sex; the second, sex and creation; the last, sex, creation, and salvation.

This interpretation makes complete sense to me. See, for example, the part of section V that reads:

Between the conception
And the creation
Between the emotion
And the response
Falls the Shadow

I understood this (before finding Grover Smith's statement) to mean that something is coming in between the cause and effect, the idea and the realization, the feeling and the reaction.

Before I end, I would like to add that, to me, Eliot (especially in the 1920s, when he wrote "The Hollow Men) frequently deals with death, both literal and cultural. He's not the only famous writer active in the wake of World War One, of course, but he's one of the best to present the war's lingering influence.