'course of action', is a name for the group of 10 kinds of either unwholesome or wholesome actions, viz.
3 bodily actions: killing, stealing, unlawful sexual intercourse;
4 verbal actions: lying, slandering, rude speech, foolish babble;
3 mental actions: covetousness, ill-will, evil views.
Unwholesome mental courses of action comprise only extreme forms of defiled thought: the greedy wish to appropriate others' property, the hateful thought of harming others, and pernicious views. Milder forms of mental defilement are also unwholesome, but do not constitute 'courses of action'.
3 bodily actions: avoidance of killing, stealing, unlawful sexual intercourse;
4 verbal actions: avoidance of lying, slandering, rude speech, foolish babble; i.e. true, conciliatory, mild, and wise speech;
3 mental actions: unselfishness, good-will, right views.
Both lists occur repeatedly, e.g. in A.X.28, 176; M.9; they are explained in detail in M.114, and in Com. to M.9 (R. Und., p. 14), Atthasālini Tr. I, 126ff.