http://www.polishroots.org/surnames/surnames_endings.htm the above link is about suffices, sort of standard endings, like the
-ski in many Polish names. This suffix means something like "one from...". It is a sort of genetivus (if that says something to you). The way you translate it depends a bit from the stem, because Janski would mean 'one from Jan', but better in this case would be "son of Jan', because this is meant with Janski. Then, the suffix
-ewski would mean something like "of the...".
Better do an example:
kowal is 'smith' in Polish.
kowalew or
kowalewo means '(place) of the smith'
kowalewski is 'one from the place of the smith'
Blazejewski falls thus apart in
blazej- ,
-ew- and
-ski , meaning 'one from the place of the [blazej]'.
so i've searched and found that Blazej is a firstname. The meaning and origin of it you'll can find following this link:
http://www.behindthename.com/php/search.php?terms=blazej&nmd=n&gender=both&operator=or Blazejewski: "one from the place of Blazej"