diffrwyth

Welsh

Etymology

From di- +‎ ffrwyth.

Adjective

diffrwyth (feminine singular diffrwyth, plural diffrwyth, equative mor ddiffrwyth, comparative mwy diffrwyth, superlative mwyaf diffrwyth)

fruitless, ineffective
Antonym: ffrwythlon

Mutation

Welsh mutation
radical	soft	nasal	aspirate
diffrwyth	ddiffrwyth	niffrwyth	unchanged
Note: Some of these forms may be hypothetical. Not every possible mutated form of every word actually occurs.