Choose the appropriate word which can be substituted for the given sentence: 'One who knows everything'.

Choose the appropriate word which can be substituted for the given sentence: 'An extremely old person that behaves like a fool'.

Choose the appropriate word which can be substituted for the given sentence: '$A$ man who speaks less in the forum'.

Choose the appropriate word which can be substituted for the given sentence: $A$ person who remains confident or hopeful about the success of something.

Choose the appropriate word which can be substituted for the given sentence: 'Animals feeding on plants'.

Choose the appropriate word which can be substituted for the given sentence: 'List of the business or subjects to be considered at a meeting'.