'watery-eyed' is formed from the adjective 'watery' and the adjectival suffix '-eyed'. 'watery' originates from Old English 'wæterig' (from 'wæter' meaning 'water') where the suffix '-ig' (later '-y') meant 'characterized by'. 'eyed' comes from Old English 'ēage' meaning 'eye' plus the adjectival suffix.

'watery' developed from Old English 'wæterig' into Middle English forms like 'watery' meaning 'full of water' and later combined with the word 'eye' (Old English 'ēage') to form compound adjectives such as 'watery-eyed' in Early Modern English, eventually becoming the modern English 'watery-eyed'.

Initially, elements meant 'characterized by water' (for 'watery') and 'eye' (for 'eyed'); over time the compound came to mean specifically 'having eyes that are watery or tearful' rather than simply 'like water'.