whats the missing word

[hazelcs]

as (4) as mutton
as (4) as a snail
as (5) as mud

[sddsddean]

as clear as mud

[sddsddean]

as slow/fast as a snail

[sir.prize]

dead as mutton

[heathfield]

Alternatively, as daft as mutton, as clear as mud

[heathfield]

Sorry Sddsddean, I meant 'as thick as mud'! Just proved it!