adjective
dear, nice
A1
lieb means 'dear' or 'nice', an adjective expressing affection or pleasantness. It's gradable: comparative lieber and superlative am liebsten. Antonym: böse. Note: lieber also functions as adverb meaning 'rather' (Ich würde lieber...). Regular adjective inflection applies when used attributively with gender/number endings. It can be used sincerely or ironically.
Examples
Die Nachbarin war sehr lieb, weil sie immer half, wenn jemand Probleme hatte.
The neighbor was very kind because she always helped when someone had problems.
Das ist aber lieb von dir!
That's so nice/kind of you!
Liebe Grüße an alle, besonders an dich, mein lieber Freund.
Love to everyone, especially to you, my dear friend.
Details
Mnemonics
Imagine a kind person giving a small gift — that's 'lieb'.
Like English 'love' (lieb ~ love) to remember affectionate meaning.
Notes
Used to express affection or niceness. Comparative 'lieber', superlative 'am liebsten' (note 'am liebsten' can mean 'preferably').