Say it's okay on tap and key for the odd rugby period of sluggishness (8)
I believe the answer is:
lethargy
'sluggishness' is the definition.
(I know that sluggishness can be written as lethargy)
'say it's okay on tap and key for the odd rugby period' is the wordplay.
I cannot quite see how this works, but
'tap' could be 'h' (H for the hot tap) and 'h' is found in the answer.
'key' could be 'g' (musical key) and 'g' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for lethargy that I've seen before include "Stringed instrument" , "Torpor" , "Lack of energy and enthusiasm" , "Weariness" , "Lassitude, languor" .)