The Romans had a word for hard cash, as opposed to money or wealth in general: nummi.
One could therefore say: Civitas nummorum expers.
I think it would not be lost on the Romans that this would not mean sine opibus et divitiis, and one could still transfer wealth somehow in such a society; after all, they did have bankers and kept books (tabulae).
A relevant discussion of this question with some interesting examples can be found in Calboli, Gualtiero (2009: 145-146). "Latin Syntax and Greek". In Philip Baldi & Pierluigi Cuzzolin (eds.). New Perspectives on Historical Latin Syntax vol. 1,pp. 65–193. Berlin-New York: De Gruyter. Here is the relevant quote (bold mine: Mitomino):
You decline the main noun and keep the genetive of the other noun.
A relationship by marriage is: affinitas.
A relationship by marriage with a very good man is: affinitas viri optimi.
I congratulate you on your relationship by marriage with a very good man is: Gratulor tibi affinitatem viri […] optimi (Cicero, Epistulae ad familiares, 8,13); overly literal ...
Unless you specifically want a Latin compound, the Greek-based terms autogenous (adj.), autogene (n.) suggest themselves. Some Googling shows they're already in existence with more or less the meaning you want.
Quite probably, your invented examples Infans lavandus clamabat and Urbs nobis capienda militiam novam paraverat would sound quite odd to a native speaker of Latin.
Note that the attributive use of verbal adjectives in -nd- was very restricted in Latin. As pointed out by Pinkster (2015: 998), "the attributive use of gerundives is almost entirely restricted ...
As Cerberus points out, plus is an adjective and has therefore the gender and number and case of the main word.
There is also the corresponding adverb plus, which could be seen as the neuter accusative of the adjective.
The word magis is also an adverb, but not synonymous with plus.
I assume your question concerns the adverbial usage, but do bear in mind ...
The usage of plus and other forms like plures, plura seems to be a little complicated and depend on the grammatical number.
Plus can be used as a singular noun or an adverb
The form plus looks like a singular neuter adjective in the nominative/accusative case.
However, what I've read is that this word in the singular is only used as an adverb (the nominative/...
The adjective plus means "more". If you want to say more than, you can either use the (often elliptical) conjunction quam, or an ablative of comparison.
[Ego] habeo plura capita quam homines [capita habent].
[Ego] habeo plura capita quam [ego habeo] caudas.
After quam, you would use the same case as the first element of the comparison, so ego ...
According to Vester (1991; see the full reference below), the gerund can take an object in the following contexts:
genitive: ars scribendi (epistulam)
ablative: scribendo (epistulam) tempus tero
nominative: mihi (epistulam) scribendum est
According to Vester, "it is evident that scribendum is a gerund in mihi epistulam scribendum est, but for some ...
A se factus is both an adjective and a noun, as indeed are all Latin adjectives. It literally means "having been made by himself". A se facta is the feminine version of the same noun.
One possible problem with this is that a se factus has to be a third person noun. You can't really say, "I am a se factus." You have to say a me factus sum. ...
Answer to my question:
Here it is answered on this article:
The final result turned from points into percentages of change, permits us to
state that on the basis of our tentative point-system the percentage of stressedvowel change from the original Latin for each of the seven languages is as follows: French, 44%; Portuguese, 31%; Proven~al, 25%; Rumanian, ...
When first introducing the concept in a Latin text, you probably need to explain what is meant.
Bear in mind that while nummus may principally refer to cash, I cannot think of a way to say "cashless" that would probably not mean "poor" to a Roman — or many other people.
Therefore context and explanation is needed to make the concept ...