Is there a command line spell to drop a column in a CSV-file?

I believe this is specific to cut from the GNU coreutils:

$ cut --complement -f 3 -d, inputfile
1111,2222,4444
aaaa,bbbb,dddd

Normally you specify the fields you want via -f, but by adding --complement you reverse the meaning, naturally. From 'man cut':

--complement
    complement the set of selected bytes, characters or fields

One caveat: if any of the columns contain a comma, it will throw cut off, because cut isn't a CSV parser in the same way that a spreadsheet is. Many parsers have different ideas about how to handle escaping commas in CSV. For the simple CSV case, on the command line, cut is still the way to go.

If the data is simply made of comma-separated columns:

cut -d , -f 1-2,4-

You can also use awk, but it's a bit awkward because while clearing a field is easy, removing the separator takes some work. If you have no empty field, it's not too bad:

awk -F , 'BEGIN {OFS=FS}  {$3=""; sub(",,", ","); print}'

If you have actual CSV, where commas can appear inside fields if properly quoted, you need a real CSV library.