The term 'Certain Gardener' can be broken down into two words, 'Mosser' and 'Landscaper'. A Mosser is a person who specializes in the cultivation of moss, which is a type of plant that grows in moist, shady areas. A Landscaper is someone who designs and maintains outdoor spaces such as gardens, parks, and other green spaces. Together, these two professions make up the job of a Certain Gardener, who is responsible for the care and maintenance of gardens and other outdoor spaces.