boyfriend
Synonym discussion
Sense: noun/1
'Boyfriend' usually suggests an ongoing romantic relationship. 'Partner' is broader and more neutral: it can describe a serious relationship without focusing on gender, and it often sounds more adult or long-term. 'Date' is lighter and less committed; someone can be your date for one evening without being your boyfriend. 'Lover' is much more intimate and often literary, and it may suggest a sexual relationship or secrecy rather than everyday dating. If you are talking about a steady person you are seeing, 'boyfriend' is the natural word. You might say 'I'm bringing my boyfriend to dinner,' but 'I have a date on Friday' if the relationship is not established yet.
Etymology
'Boyfriend' is a native English compound joining 'boy' and 'friend'. 'Friend' comes from Old English 'freond', while 'boy' is recorded from Middle English and has uncertain earlier roots. The compound first had the broad sense 'male friend', but modern everyday English narrowed it so the romantic meaning is now the normal one. The fashion adjective appeared much later from the noun, especially in shop language such as 'boyfriend jeans', where the idea is a loose cut that looks as if it came from a man's wardrobe.