Account put in words lacking introduction to be precise (5)
I believe the answer is:
exact
'precise' is the definition.
(I know that precise can be written as exact)
'account put in words lacking introduction' is the wordplay.
'account put' becomes 'ac' (I can't justify this - if you can you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'words' becomes 'text' (I've seen this before).
'lacking introduction' means to remove the first letter.
'text' with its first letter removed is 'ext'.
'ac' going within 'ext' is 'EXACT'.
'to be' is the link.
Can you help me to learn more?
(Other definitions for exact that I've seen before include "Strict" , "Spot-on" , "Correct; insist on" , "Precise, accurate" , "Particular" .)