'salt-susceptible' originates from modern English as a compound of 'salt' and 'susceptible'. 'Salt' comes from Old English 'sealt' meaning 'salt', and 'susceptible' comes from Latin 'susceptibilis' via Middle French/Latin, where 'sus-' meant 'under' and 'capere' (root) meant 'to take' (sense: able to receive or be affected).

'salt-susceptible' is a modern compound formed by joining the noun 'salt' (Old English 'sealt') with the adjective 'susceptible' (from Latin 'susceptibilis' → Old French/Middle English 'susceptible'), producing the descriptive adjective now used in technical contexts (agronomy, plant physiology, materials science).

Individually, 'susceptible' historically meant 'able to be influenced or affected'; when combined with 'salt' it has come to mean specifically 'readily harmed or affected by salt', a more specialized modern sense.