makittaqanngitsoq

[makitːaqaŋːitsoq]

Someone who hasn't mastered the art of rolling over in a kayak.

​Greenlandic, Kalaallisut – 57,000 speakers, Greenland, USA (Alaska), Canada

A common feature of ‘untranslatable’ words is translations which add contextual information. For example, the above definition mentions kayak, mastery, and rolling. However, these concepts are only implied. Consider the breakdown of the word:

makittaq -a           -nngit -soq
makittaq -qar        -nngit -toq        -0
rising      -have      -not    -intrans  -absolutive.singular
be unable to get upright

Linguists call this complex word structure ‘polysynthesis’.

​Source: Smilla’s Sense of Snow (1:04:58). 
Credit: Steven Bird, Anthony Woodbury