Agreement of tout

Question

In “dont les noms sont tout aussi appétissants”, why doesn’t “tout” agree with the subject (“les noms”)? I was expecting to see “tous”.

Accepted Answer

Hi Brian, 
The rules which decree when to agree the adverb 'tout' with the thing they modify are complex so  I advise you to work through the following lesson.
Tout, tous, toute, toutes = Everything, all (of them), whole
In 'tout appétissants',  'tout' is an adverb and doesn't change when the adjective is masculine. In the case of feminine adjectives, the rules are even more complicated.
Hope this helps!

Answer

Tout in this sentence is used as an adjective: tout appétissants, not as an adjective for noms.Tous les noms sont appétissants. -- All the names are appetizing.Les noms sont tout appétissants. -- The names are entirely appetizing. (Or, more colloquially: the names are totally appetizing.)

Answer

Chris's answer may be a little confusing because he inadvertently wrote "adjective" instead of "adverb" in the first bit of his reply. "Tout" is an adverb when modifying "appétissants" here, and not an adjective for "noms". Apart from that little slip, his answer is correct.