The five languages of the Northwest Caucasian family (also known as West Caucasian or Abkhaz-Adyghe), namely West Circassian, Kabardian, Ubykh, Abkhaz, and Abaza, are remarkable for their high degree of polysynthesis. This manifests itself in complex words that bear a lot of information on arguments and the characteristics of a situation, and which presumably can be constructed in the course of speech. Content words usually consist of several morphological zones within which certain permutations of morphemes are possible. Both prefixes and suffixes occur, with some morphemes being capable of appearing either as a prefix or a suffix, depending on the form. The predicate shows ergative-based cross-reference of core arguments and indirect objects introduced by applicatives, extensive use of the causative (including double causativization), highly developed means of expressing locational semantics within the predicate, and intricate tense-modality-aspect and polarity systems. Although classical noun-to-verb incorporation does not occur, there are constructions akin to incorporation, especially in the nominal domain. Nouns constitute a subclass of a broad class of predicates (both morphologically and syntactically) and hence may take the basic predicate morphology. At the same time, they form word-like nominal complexes with their attributes, and show specific head-marking possessive morphology (in West Circassian even distinguishing alienable and inalienable possession). Definiteness/specificity is regularly expressed either by articles (in Abkhaz, Abaza and Ubykh) or by the presence/absence of core case marking (in West Circassian and Kabardian). Morphemes demonstrate features that are not typical of morphemes in Standard Average European languages, including a high degree of autonomy reflected in affix order variation, widespread morphological recursion, occasional reduplication and even the ability to attach to complex syntactic constituents.