Powerful drive, with spirit: nineteen more needed for century? (7)
I believe the answer is:
lustrum
'nineteen more needed for century?' is the definition.
(a lustrum is a period of five years)
'powerful drive with spirit' is the wordplay.
'powerful drive' becomes 'lust' (I can't justify this - if you can you should believe this answer much more).
'with' means one lot of letters go next to another.
'spirit' becomes 'rum' (I've seen this before).
'lust'+'rum'='LUSTRUM'
(Other definitions for lustrum that I've seen before include "several years" , "Five-year period" , "Period of five years" , "Period of 20 ac years" .)