a couple of points on this one...
1) it's not a new word (which doesn't excuse it), it's been around since 1969, when it was evidently coined by the US Dept. of Defense
2) since it's a US coinage, the proper spelling is weaponization
3) as bill points out, there don't seem to be any better words at this point in time
oops... I lied, that was three points. as long as I've overextended my stay, I might as well throw in this cross thread:
'weapon' is a an archaic verb which has been almost completely vanquished by 'arm'.
1969 U.S. Dept. Defense Appropriation Bill 1970 (91st Congress 1 Sess., House Rep. 698) 72 Aircraft Weaponization (advanced and exploratory development) was reduced. 1973 Black Panther 7 Apr. 10/2 Observers worry that the fledgling crime protection industry may follow a similar line, with huge profits made in this industry supporting a new domestic lobby for more weaponized solutions to the anger of the ghetto, the barrio and the poor white hollow. 1976 Aviation Week 1 Nov. 19/2 He said the Navy plans to build a 3,000-ton ‘weaponized’ surface-effect ship. 1982 N.Y. Times 23 Mar. a–14/2 Chemical warfare agents were+weaponized with Soviet assistance in Laos, Vietnam and Kampuchea. 1983 Aviation Week 17 Jan. 27/2 He cited an alarming trend toward the weaponization of space as the reason for his new emphasis on the civilian uses of space. 
