'waterbird-like' originates from Modern English as a compound of 'waterbird' + the suffix '-like' (meaning 'having the form or nature of').

'waterbird' itself is a compound of Old English 'wæter' (water) and 'bridde'/'bird' (bird); the suffix '-like' goes back to Old English 'līc' meaning 'body, form' and later developed into a productive adjectival suffix in Middle and Modern English, forming compounds such as 'child-like' and 'waterbird-like'.

Initially formed to mean 'having the form or nature of a waterbird'; the meaning has remained stable as a descriptive compound.