Sarissa was a 4-7 m long pike introduced from Philip II the Macedon for the forward ranks of Macedonian army. It was a development of dory( δόρυ) , a one-handed spear :

the possible etymology of it is either albanian word ‘dorë’ which means hand:

or the other albanian word dru which means wood or tree:

Sarissa is a long version of dory. Its main function was not only to hit the enemy but not to allow them to reach Macedonian ranks.

It’s is very probable and makes a complete sense in Albanian language that the word derives from the Albanian verb *arrij which means to reach.

We have to do with a compound word where:
s‘———–> is a privative preposition and is a short form for nuk which means not or un.
arrish——–> is the the verb arrij in one of its inflected forms

The meaning of the word is: the UNREACHABLE, which takes the meaning from the excessive length of this particular pike, which has been used as an ostacle to hold back the enemy in order they never reach and thus not harming the forward ranks of these Albanian army formations.

Thus, the sarissa was the spear peculiar to the Macedonians. This was used both to throw and as a pike. It exceeded in length all other missiles.—The Thracian romphea, which had a very long point, like the blade of a sword, was probably not unlike the sarissa.—With these weapons we may alao class the Illyrian sibina, which resembled a hunting-pole.

A smaller dictionary of Greek and Roman antiquities – by William Smith, pg.201