1prevent (a plan or attempted action) from progressing, succeeding, or being fulfilled:the rescue attempt was frustrated by bad weather
prevent (someone) from doing or achieving something:in numerous policy areas, central government has been frustrated by local authorities
2cause (someone) to feel upset or annoyed as a result of being unable to change or achieve something: (as adjective frustrating)it can be very frustrating to find that the size you want isn’t there
frustratingly
adverb
[as submodifier]:progress turned out to be frustratingly slow