Full Idea
Someone who acquires the word 'gob' just by being reliably told that it is synonymous with 'mouth' knows what 'gob' means without being fully competent to use it.
Gist of Idea
You might know that the word 'gob' meant 'mouth', but not be competent to use it
Source
Timothy Williamson (The Philosophy of Philosophy [2007], 4.7)
Book Reference
Williamson,Timothy: 'The Philosophy of Philosophy' [Blackwell 2007], p.129
A Reaction
Not exactly an argument against meaning-as-use, but a very nice cautionary example to show that 'knowing the meaning' of a word may be a rather limited, and dangerous, achievement.