1. close acquaintance with or knowledge of something
2. relaxed friendliness or intimacy between people
3. inappropriate informality in behavior or speech
Usage: often disapproving

Examples

• Her familiarity with the software made training unnecessary.
• Years of working together had bred a comfortable familiarity between them.
• I was surprised by his familiarity with classical music.
• The student’s familiarity with the teacher was inappropriate.
• Familiarity with local customs helped her adjust quickly.
• His familiarity in addressing the CEO shocked everyone.
• She spoke with the familiarity of an old friend.