Some common synonyms of relevant are applicable, apposite, apropos, germane, material, and pertinent. While all these words mean "relating to or bearing upon the matter in hand," relevant implies a traceable, significant, logical connection.

// found material relevant to her case

While in some cases nearly identical to relevant, applicable suggests the fitness of bringing a general rule or principle to bear upon a particular case.

// the rule is not applicable in this case

The words material and relevant can be used in similar contexts, but material implies so close a relationship that it cannot be dispensed with without serious alteration of the case.

// facts material to the investigation