The head of staff talks too much of difficulties (5)
I believe the answer is:
snags
'difficulties' is the definition.
(snag is a kind of difficulty)
'the head of staff talks too much of' is the wordplay.
'the head of' says to take the initial letters.
'talks' becomes 'nag' (I can't justify this - if you can you should give a lot more credence to this answer).
'too' becomes 'so' (synonyms).
'much of' means to remove the last letter (I've seen 'much' mean this (much but not all of the word)).
The initial letter of 'staff' is 's'.
'so' with its last letter taken away is 's'.
's'+'nag'+'s'='SNAGS'
Can you help me to learn more?
(Other definitions for snags that I've seen before include "Unexpected obstacles" , "Problems" , "Hitches" , "Unforeseen obstacles" , "Drawbacks" .)