If you would like an adverb or conjunction to be able to deal with either a verb or noun argument use the following pattern.
test =: 1 : 0 if. (4!:0 < 'm') do. NB. Verb argument: Safe to use u in this section but not m u y else. NB. Noun argument: Safe to use m in this section but not u m+y end. )
- +: test 2
4
- 1 test 2
3
the u and v arguments can represent either verbs or nouns, so its possible to try to define your adverb or conjunction without this clear separation, but I'd still recommend the above.