A verb takes two arguments and can be called with its arguments to left and right. A verb can also be called with the same syntax as functions, for example:
q)2 3 5 + 10 12 13 15 q)+[2 3 5;10] 12 13 15
If only the left argument is given, the result is a function of one argument:
q)f:2 3 5 + q)f 10 12 13 15
Several verbs are defined by the q system. A new verb can be defined only by applying an adverb to an existing verb, i.e. you cannot define a verb using explicit definition or function projection.