The word 'flattish' mainly means partially or somewhat flat in shape, size, or appearance. In place of the term 'flattish', various other words can be used based on its context and meaning. Words like level, even, smooth, planar, and uniform can be used as synonyms for 'flattish'. While 'level' defines a surface that is flat and even, 'even' implies equal in height or surface level. Also, 'smooth' suggest a flat surface free from any roughness or ruggedness, and 'planar' implies a surface that is perfectly flat. Furthermore, 'uniform' relates to a homogenous or constant surface with no variation or irregularity. These words related to 'flattish' can add diversity and accuracy to your writing.