Turn, divert, deflect, avert, sheer are comparable when they mean to change or cause to change course or direction.
Turn is the most comprehensive of these words and the widest in its range of application. It may be used in reference to any change in course or direction of something movable, no matter how small or how large an arc is traversed, but it usually requires qualification.
It may also be used in reference to something (as things that show a drift, a bent, or a tendency or persons or things that can respond to an influence) which follows a figurative course or proceeds in a definite direction.
Divert may be preferred to turn when there is an implication of an imposed change in an existent or a natural course or direction. When used in reference to a person’s concerns (as thoughts, interests, attention, or intentions) it often presupposes mental concentration, fixity of attention, or resoluteness of purpose; therefore, when an attempt to alter the situation (as by distracting, dissuading, or sidetracking) is to be suggested, divert is the appropriate word.
Deflect , in contrast to divert , implies a turning (as by bouncing, refracting, or ricocheting) from a straight course or a fixed direction. In its extended use it is chiefly referred to thoughts, purposes, or interests that pursue a rigid or clearly defined course or direction; consequently the word sometimes connotes deviation or aberration.
Avert implies a turning away from what is before one physically or mentally; it is used chiefly in reference to something at which one has been looking or of which one has been thinking and carries commonly a strong implication of avoidance and, often, a further suggestion of repugnance.
Sheer is used basically in reference to the turning of a boat or ship from its course especially in an emergency. In its extended use the word commonly implies a sudden or conspicuous turning aside from a path or course that has been followed.