The root in all cases is ranj (the n is palatal), to be dyed, whose cognates are obvious in Greek. The root gave rise to various words ranging from red (and thence to glow and silver), blood, black, night, mist (and thence to dust and semen), gloom or even washerman (who was often also the dyer) just to take a few examples. The colouring could be grammatical (e.g. a nasal vowel is a coloured vowel) or emotional (flushed or gloomy coming respectively from the red or dark connotations) and thence came the meanings of to be moved, excited, glad, delighted, attracted, fall in love, etc. Verbal forms also express transitive actions like to color etc.
The word ranjana has ranjanI and ranjinI as its feminine, the latter is the form used almost exclusively in names, and is more common as a name.