Definition of rainfast in English:

rainfast

Line breaks: rain|fast
Pronunciation: /ˈreɪnfɑːst/

adjective

(Of a chemical spray or other substance) not able to be washed away by rain.
More example sentences
  • This spray is longer lasting than the copper sprays used on tomatoes, and it is rainfast.
  • Allow at least six hours for the glyphosate products to become rainfast.
  • This product is cheaper, has a better safety profile, controls both types of rhizomes and is rainfast after 2 hours.

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