Contents of sack seen repeatedly by one with a plant (6)
I believe the answer is:
acacia
'a plant' is the definition.
The answer is an example.
'contents of sack seen repeatedly by one' is the wordplay.
'contents of' means to look at the middle letters (letters inside the word).
'seen' means one lot of letters go next to another.
'repeatedly' becomes 'cia' (I am not sure about this - if you are sure you should believe this answer much more).
'by' is a charade indicator (letters next to each other).
'one' becomes 'a' (a thing is one thing).
The middle of 'sack' is 'ac'.
'cia' put after 'a' is 'acia'.
'ac' put next to 'acia' is 'ACACIA'.
'with' acts as a link.
Can you help me to learn more?
(Other definitions for acacia that I've seen before include "Subtropical shrub or tree" , "Australian shrub" , "Gum-yielding tree ir shrub" , "Thorny flowering shrub" , "Plant such as the Australian wattle" .)