Shade:

the svelte/ Stilettos of a frozen stillicide —

Kinbote:

Lines 34-35: Stilettos of a frozen stillicide

How persistently our poet evokes images of winter in the beginning of a poem which he started composing on a balmy summer night! The mechanism of the associations is easy to make out (glass leading to crystal and crystal to ice) but the prompter behind it retains his incognito. One is too modest to suppose that the fact that the poet and his future commentator first met on a winter day somehow impinges here on the actual season. In the lovely line heading this comment the reader should note the last word. My dictionary defines it as "a succession of drops falling from the eaves, eavesdrop, cavesdrop." I remember having encountered it for the first time in a poem by Thomas Hardy. The bright frost has eternalized the bright eavesdrop. We should also note the cloak-and-dagger hint-glint in the "svelte stilettos" and the shadow of regicide in the rhyme.

.......................................

I had almost given up exploring avenues into VN's "stillicide" but, besides Giulia's confirmation of its use in Italy ( mainly figurative, referring to repetitive, insistent activity), I also found it mentioned in a Portuguese-French dictionary as: "ecoulement goute à goute", just like it was described by C.Kinbote ( and fig. "rhume de cerveau").

In Spanish, it may indicate, figuratively, "abortion" and "the menses" ( Cf. "Éxito a todos los poetas......hacer arte (!) con el estilicidio de sus menstruaciones intelectuales..." "La Selva de sus Vestidos, los Judas de sus Venas", by Juan Rafael Coronel Rivera ).

Several different dictionaries in Brazil relate "estilicídio" to "estalicídio" ( Greek stalaktós, stalactite/stalagmite), also applied to various symptoms of a cold and
constipation ( intestinal troubles).

So, just as Kinbote annotated, the common meaning of this word refers to "constant drops falling from the eaves", which may harden and form daggerlike projections by the sedmimentation of rock or crystallization of congealed ice-droplets.

Literaly, very literaly then, "estilicido" indicates "droppings from the eaves" that might harden in the shape of a dagger( stiletto).

Figuratively its use varies from snoopy eaves-dropping (Kinbote?), to boring insistence, constipation, rheumy eyes, running nose, drops of blood, menses, abortion ...

Was Kinbote's dictionary ( as he mentioned it explicitly in his note fom his Cedarn cave) also a Websters 2nd ??