Lady's incomplete pattern (4)
I believe the answer is:
norm
'pattern' is the definition.
(I have seen 'Typical pattern' mean 'norm' so perhaps 'pattern' could also mean 'norm')
'lady's incomplete' is the wordplay.
'lady' becomes 'norma' (I've seen this before).
'incomplete' means to remove the last letter.
'norma' with its last letter removed is 'NORM'.
(Other definitions for norm that I've seen before include "Benchmark" , "Standard, average" , "Standard level of performance" , "Expected standard" , "Standard considered to be representative" .)