Diffident is a word that describes someone who is shy, lacking in confidence, or reluctant to assert themselves. There are several synonyms for diffident that can help provide a more nuanced understanding of this concept. For instance, timid is a word that describes someone who lacks self-assurance and is easily frightened or hesitant. Similarly, bashful is a term that often refers to someone who is shy and easily embarrassed. Other synonyms for diffident include reserved, modest, reticent, and withdrawn. Each of these words captures a unique aspect of diffidence, highlighting the complexity of this particular personality trait.