Thus, many monosyllables have no genitive plural: as, #aes#, _copper_,
#cor#, _heart_, #cōs#, _whetstone_, #dōs#, _dowry_, #ōs#, _face_, #pāx#,
_peace_, #pix#, _pitch_, #rōs#, _dew_, #sāl#, _salt_, #lūx#, _light_;
many words have no genitive, dative, or ablative plural: as, #hiemps#,
_winter_; especially neuters: as, #fār#, _spelt_, #fel#, _gall_, #mel#,
_honey_, #pūs#, _matter_, #rūs#, _country_, #tūs#, _frankincense_. Many
words in #-tu-# (#-su-#) have only the ablative (235). For #-ē-# stems,
see 600. Other words more or less defective are #exlēx#, #exspēs#, #fās#
and #nefās#, #īnfitiās#, #inquiēs#, #īnstar#, #luēs#, #nēmō#, #opis# and
#vicis# genitives, #pondō# and #sponte# ablatives, #secus#, #vīs#. Many
adjectives ‘of one ending’ want the nominative and accusative neuter
plural and genitive plural.
431. Some adjectives are altogether indeclinable: as, #frūgī#,
_thrifty_, an old dative; #nēquam#, _naughty_, an old accusative;
#quot#, _how many_; #tot#, _so many_; and most numerals (637). These
adjectives are attached to any case of a substantive without varying
their own forms.