The first matters are to be sneezed at (7)
I believe the answer is:
tissues
'the first matters are to be sneezed at' is the definition.
I can't judge whether this defines the answer.
'the first matters are to be sneezed at' is the wordplay.
'first' says to take the initial letters.
'matters' becomes 'Is' (I is an example).
'are to be sneezed at' becomes 'sues' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The initial letter of 'the' is 't'.
't'+'is'+'sues'='TISSUES'
Can you help me to learn more?
(Other definitions for tissues that I've seen before include "Sheets of very thin paper" , "Soft, thin pieces of paper" , "Thin skins or papers" , "Paper handkerchiefs" , "not to be sneezed at? Au contraire!" .)