Full Idea
Geach puts 'good' in the class of attributive adjectives, such as 'large' and 'small', contrasting such adjectives with 'predicative' adjectives such as 'red'.
Gist of Idea
'Good' is an attributive adjective like 'large', not predicative like 'red'
Source
report of Peter Geach (Good and Evil [1956]) by Philippa Foot - Natural Goodness Intro
Book Reference
Foot,Philippa: 'Natural Goodness' [OUP 2003], p.2
A Reaction
[In Analysis 17, and 'Theories of Ethics' ed Foot] Thus any object can simply be red, but something can only be large or small 'for a rat' or 'for a car'. Hence nothing is just good, but always a good so-and-so. This is Aristotelian, and Foot loves it.