Line for playing on, put in neatly, properly and austerely (12)

'austerely' is the definition.
Both the answer and definition are adverbs.
Perhaps they are linked in a way I don't understand?

'line for playing on put in neatly properly' is the wordplay.
I cannot really see how this works, but
'line' could be 'string' (string line is a kind of line) and 'string' is found within the answer.
an anagram of 'neatly' is 'aently' which is located in the left over letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).

'and' is the link.

Can you help me to learn more?