Let no corrupt communication proceed out of your mouth, but that which is good to the use of edifying, that it may minister grace unto the hearers.
Corrupt, х sapros (G4550)] - 'insipid;' without 'the salt of grace' (Colossians 4:6); so worthless, then becoming corrupt: included in "foolish talking" (Ephesians 5:4). Its opposite is "that which is good to ... edifying."
Communication - language.
That which ... - Greek, 'whatever is good.'
Use of edifying - literally, 'for edifying in respect of the need;' according as the occasion and present needs of the hearers require-now censure, at another time consolation. Even words good in themselves must be introduced seasonably, lest they prove injurious instead of useful. Trench, Not vague generalities, which would suit a thousand other cases equally well or ill: our words should be as nails fastened in a sure place, words suiting the present time and the present person, being 'for the edifying of the occasion.'
Minister - Greek, 'give.' The Word 'gives grace (a blessing: Ellicott) to the hearers' when God uses it as His instrument for that purpose.