A condensation (or dehydration) reaction is when water is removed in the process of joining two monomers to form a polymer. Examples are:

Glucose + Glucose becomes Maltose + water
Maltose + Glucose becomes Polysaccharide + water
Glycerol + 3 Fatty acids becomes Triglyceride +3 water molecules
Amino acid + Amino acid becomes Dipeptide + water
Dipeptide + Amino acid becomes Polypeptide + water

A hydrolysis reaction is when water is used to split a polymer into its constituent monomers. Examples are:

Maltose + 1 water becomes 1 Glucose + 1 Glucose
Polysaccharide + water becomes Maltose + 1 Glucose
Triglyceride +3 water molecules becomes Glycerol + 3 Fatty acids
Dipeptide + water becomes 1 Amino acid + 1 Amino acid
Polypeptide + water becomes Dipeptide + 1 Amino acid