Wrestle, tussle, grapple, scuffle mean to struggle with an opponent at close quarters.
Wrestle basically implies a struggle for mastery by gripping with hands, arms, and legs, often in ways governed by fixed rules; the term connotes the exercise of skill and ingenuity as well as strength. In its extended use wrestle also implies a struggle for mastery, but it may suggest either a striving for superiority or for a particular advantage or a laborious effort (as in understanding, in seeking, or in overcoming).
Tussle also suggests a struggle for mastery, but it implies determination rather than skill or ingenuity and willingness to accept the rough-and-tumble conditions of such a struggle.
Grapple stresses the action of taking hold of or coming to grips with; the term carries a stronger implication of being in a position to gain the mastery and, usually, of a successful struggle.
Scuffle may imply brief, confused, usually not very serious fighting involving much scrambling and noise. It may suggest hurry or superficiality in overcoming difficulties.