'slipper-shaped' originates from Modern English by combining the noun 'slipper' and the adjectival suffix '-shaped' (meaning 'having the form of'). 'slipper' comes from Old English 'sliper' (a loose shoe) ultimately related to the verb 'slip' (to slide), and 'shape' comes from Old English 'sceap'/'scēapian' (to form).

'slipper' changed from Old English 'sliper' (derived from 'slipan', to slip) through Middle English 'slipper' and became the modern English 'slipper'. 'shape' developed from Old English 'sceap'/'scēapan' into Middle English 'shape' and then modern English 'shape'; the compound form 'X-shaped' is a productive Modern English construction used to mean 'having the shape of X'.

Initially, the elements referred separately to 'a loose shoe' ('slipper') and 'form' ('shape'), but combined in Modern English they mean 'having the form of a slipper' as a descriptive compound adjective.