something which seems to show that a successful period is beginning or that a situation is improving when it is not.

His victory in the French Open proved to be a false dawn after he failed to win another title for the next five years.

• be close to the mark
• be coining it
• be cold comfort
• be cold enough to freeze the balls off a brass monkey
• be coming apart at the seams
• be comme il faut
• be compos mentis
• be conspicuous by absence
• be conspicuous by your absence
• be cooked to a turn
• be cooking on gas
• be cup of tea
• be cut from the same cloth
• be cut to the bone
• be damned
• be damned if do and damned if don't
• be damned if do and damned if you don't
• be damned if you do and damned if don't
• be damned if you do and damned if you don't
• be dead and buried
• be dead from the neck up
• be dead from the waist down
• be dead in the water
• be dead meat
• be dead on feet