In most Andian languages (cf., e.g., Cham. =ič̣-al-, Tind. =ič̣-al- etc.) the causative form of this stem is used for the verb 'to kill', and the stem itself means also 'to get spoiled, extinct; to fade, wither'. The primary meaning of it in Proto-Avaro-Andian must have been 'split, break' - cf. Av. (stem I as opposed to č̣ʷa-, stem II) -ič̣- 'split, break'. Some problems are caused by the Av. labialisation - since all Andian evidence (and also Av. -ič̣-) uniformly points to unlabialised *č̣. Av. č̣ʷá- has also the meanings 'beat, hit, pound (into smth.)' and thus may be a result of contamination with another root, *č̣ʷVn- q.v.
The original stem II of the PA root *-ič̣- is probably PA *č̣in- 'to pound, crush' (And., Cham., Tind., God. č̣in-, Kar. č̣ijã-). And. and Kar. reflect also a derived stem *=ič̣-Vn- 'to fade, wither' (And. =eč̣an-d-, Kar. =eč̣an-).