Elementary Latin: Question about masculine adjectives?

*Flies in*

Oh, hi!

That bit of your book is actually badly phrased, as not only are 'puer' and 'ager' declined pretty much the same once you get them in their "stem" form. It's just:

SG | PL

us/er | i

i | orum

o | is

um | os

o | is

(Y!A will probably mess up my table formatting but you get the idea).

The issue is that you need to know the Nominative and the Stem of each new adjective you're given. I THINK what you're asking is, will you ever be given the feminine form of the adjective, and if so, how would you know whether its masculine is '-er' or '-us'?

The short answer is that it's incredibly rare for ANY Latin dictionary to give adjectives in the feminine form. Normally, it's either given in all three forms ('bonus, bona, bonum' or 'bonus, -a, -um') or just the masculine form (because Romans were misogynistic like that...). So yes, you could potentially come across a feminine Latin adjective and not know its masculine form, but that's going to be pretty rare. What you're normally given, in any Latin dictionary (be it one from a textbook or not) is the masculine form, the feminine form, and the neuter form.

Unfortunately, we can't use "puer" as it's a noun, not an adjective, but let's use 'miser' as an example. This would be listed in your dictionary as 'miser, misera, miserum: wretched'. From this, since we're just slapping the feminine or neuter endings right on the end, we can tell that the 'stem' form (i.e., the form without any endings) of the word is indeed 'miser'. So to decline it, we just add our endings right onto 'miser'. This is called a 'strong' adjective, because it's strong enough to keep its stem in all forms. On the other hand, a weak adjective such 'pulcher' has a weak stem that collapses when we add anything other than nominative masculine singular to it: pulcher, pulchra (NOT pulchera), pulchrum (NOT pulcherum).

So the short answer is:

1) You just have to know the adjectives (seriously, there's far too many to just 'list').

2) You will normally be given the masculine and feminine and neuter form. From these, you can guess the 'stem' form onto which you add your endings (clue: it's basically just the feminine form minus the final 'a')

3) As far as declining, pulcher and animus are all declined exactly the same (in the masculine), once you know their stem form.

Here is a list of Latin adjectives. They are grouped according to type.

http://books.google.com/books?id=fEEXAAAAYAAJ&lpg=...

Edit: The pattern is inherent to the adjective. You just have to learn which ones follow which pattern. Fidus is always -us/-a/-um and pulcher is always pulcher/pulchra/pulchrum.