Adelomorphous is a scientific term that refers to an organism that lacks a definite shape or form. There are several synonyms that can be used to describe such organisms, including amoeboid, shapeless, indeterminate, formless, and unstructured. Amoeboid refers specifically to organisms that move and change shape like amoebas. Shapeless and formless both refer to the lack of a distinct shape or form. Indeterminate implies difficulty in pinpointing the exact shape or form of an organism. Lastly, unstructured suggests a lack of organization or arrangement. These synonyms can be used interchangeably to describe organisms that do not have a discernible shape or form.