Semi-regular use
One area where the derivations is ''-um-'' are nearly predictable is in pieces of clothing named after the corresponding parts of the body: ''kolumo'' 'collar' (from 'neck'); ''buŝumo'' 'muzzle' (from 'mouth'); ''manumo'' 'cuff' (from 'hand': does not mean 'glove'); ''kalkanumo'' 'heel (of a shoe)'; ''plandumo'' 'sole (of a shoe)'; ''ingvenumo'' 'jockstrap' (from 'groin'); ''hufumo'' 'horseshoe' (from 'hoof'); ''nazumo'' 'pince-nez, spectacles' (from 'nose', now uncommon). Many of these are the only word for the concept, though the last two have substitutes: ''hufofero'' (lit. "hoof-iron") and ''okulvitroj'' (lit. "eye-glasses"). (Note however that ''brakumi'' from 'arm' does not mean 'sleeve' but 'to embrace'.) In a similar vein, ''cicumo'' is a 'nipple (on a bottle)', from '(human) nipple' (body-part extension), and ''fenestrumo'' is 'shutter', from 'window' (a covering of a part). Another predictable set are formed from numbers to indicate numerical bases: ''duuma'' 'binary', ''okuma'' 'octal', ''dekuma'' 'decimal' (''dekuma logaritmo'' 'base-10 logarithm'), ''dekduuma'' 'duodecimal', ''deksesuma'' 'hexadecimal', ''dudekuma'' 'vigesimal', and ''sesdekuma'' 'sexagesimal'. Consciously using the senses is a meaning that is partially predictable, though it only fills in meanings that do not have dedicated roots like 'watch' or 'listen'. These are ''fingrumi'' 'to touch/feel/palpate' (from 'finger'); ''gustumi'' 'to taste s.t.' (from ''gusti'' 'to taste (of food)'); and ''okulumi'' 'to make eyes at' (from 'eye'). For the latter, simple ''okuli'' is often used, and it has a sexual connotation that is not predictable. The word for the senses is ''sentumo'', from ''senti'' 'to feel'. Forms of execution also take ''-um-'': ''krucumi'' 'to crucify', ''pendumi'' 'to hang', ''gasumi'' 'to gas', ''ŝtonumi'' 'to stone', ''dekumi'', ''kvaronumi'' 'to quarter', ''palisumi'' 'to impale', ''radumi'' 'to break on the wheel'. Substitute forms with ''-mortigi'' 'to kill' are nearly as common: ''krucmortigi, ŝtonmortigi,'' etc. A recent innovation is to spend time doing something, especially for pleasure. ''Butikumi'' (from ''butiko'' 'a shop') means 'to go shopping', and tends to be used in the sense of shopping for pleasure. Similarly, ''amikumi'' means 'to pass time with one's friends'; ''esperantumi'' 'to spend time using Esperanto'; ''kafumi'' 'to have a cup of coffee', ''retumi'' 'to surf the Web' (from ''reto'' 'net, Internet'), and ''urbumi'' 'to go into town' (from ''urbo'' 'town, city'). These latter words are not yet in dictionaries.List of derivations
The following is a fairly complete list of words with a reasonable degree of acceptance and that have not been covered above.See also
* The infix ''-um-'' at ''Wiktionary'' * Special Esperanto adverbs, including those with the ''ad hoc'' part-of-speech suffix ''-aŭ''References
* * {{Reflist Grammar, Infix -um