If the questioner is asking for a sample sentence, try the following: "After discussing the matter with him at length, his answer or response was completely incoherent." The basic meaning of incoherent is that an answer or response makes very little or no sense in the content of the conversation. It is almost like the babbling of an individual who is impaired mentally or is under the influence of a mind-altering substance.
Many people today are incoherent
He responded to our attempt to get him out of bed with several minutes of incoherent muttering.
The mutterings were incoherent.Nobody could work out what the incoherent notes said.
His speech was so rambling and incoherent that no one could understand what he was trying to say.
Her fervid reaction to the information was incoherent.
Billy drank beer and became totally incoherent.
Your question is incoherent.
Incoherent means expressed in a confusing way. The tired toddler was incoherent , when explaining what they wanted for lunch.
"Incoherent" is an adjective
Billy was very incoherent, So he asked his teacher for help.
Your question is incoherent.
One example could be - The drunk was too incoherent to understand. Another might be - Jack couldn't hear his wife's incoherent nagging from downstairs.