1 The main units of derivational analysis

1) those characterized by neutral stylistic reference such as: -able, -er, -ing;
2) those having a certain stylistic value such as –oid, -(i)form, -aceous, -tron.
Suffixes with neutral stylistic reference may occur in words of different lexico-stylistic layers. Cf. Agreeable/steerable (e.g. steerable spaceship), etc. As for suffixes of the second class, they are restricted in use to quite definite lexico-stylistic layers of words, in particular to terms, cf. Rhomboid, asteroid, crustaceous, cyclotron, etc.
Suffixes are subdivided into monosemantic and polysemantic. The noun-suffix –er is used to coin words denoting in particular (1) persons following some special trade or profession cf. Baker, driver, etc., (2) persons doing a certain action at the moment in question, cf. Packer, chooser, etc., (3) device, tool, implement, cf. Blotter, boiler, etc.
Many homonymic derivational suffixes can be found among those forming both different parts of speech and the same part of speech. For instance the adverb-suffix –ly added to adjective-stems is homonymous to the adjective-suffix –ly affixed to noun –stems, cf. Quickly, slowly, and lovely, friendly.
Distinction should also be made between terminal and non-terminal suffixes. Terminal suffixes take only the final position in a word, such as: the nounal suffixes –al (refusal, survival), -hood, -ness, -ship, -kin, -let, -ling.
Non-terminal suffixes can be followed by other suffixes, e.g. lead-leader-leadership, love-lovely-loveliness, etc.
In the Ukrainian language the suffixation is very productive way of word
formation. Suffixes transfer the word to another part of speech. Usually it occurs
in the noun and adjective formation, rarely in verb and other part of speech formation.
In some cases suffixes do not shift word to another part of speech.
In Ukrainian there is such kind of word-formation as the so called “zero suffixation” – the formation of new word without adding derivational affix. It may occur in:
In Ukrainian besides prefixation and suffixation exist three more waysofword-formation. They are postfixation, suffixation-postfixation and
prefixation-postfixation.
Postfixation is used to form verbs with the help of postfix –ся.
Suffixation – postfixation is the formation of words by adding suffix and
postfix to stems. Usually it occurs in verb-formation from noun and adjective stems. 
Prefixation – postfixation is the way of word – formation when prefix and postfix are added to the stem.
n morphology, derivation is the process of creating a new word out of an old word, usually by adding a prefix or a suffix. The word comes from the Latin, "to draw off," and its adjectival form is derivational.
Linguist Geert Booij, in "The Grammar of Words," notes that one criterion for distinguishing derivation and ​inflection "is that derivation may feed inflection, but not vice versa. Derivation applies to the stem-forms of words, without their inflectional endings, and creates new, more complex stems to which inflectional rules can be applied.⁸"
The derivational change that takes place without the addition of a bound morpheme (such as the use of the noun impact as a verb) is called zero derivation or conversion.