-stersuff.1. One that is associated with, participates in, makes, or does: songster. See Note at pollster.2. One that is: youngster.[Middle English, from Old English -estre, female agent suff.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.-ster suffix forming nouns 1. indicating a person who is engaged in a certain activity: prankster; songster. Compare -stress 2. indicating a person associated with or being something specified: mobster; youngster. [Old English -estre]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014-ster a suffix used in forming nouns, often derogatory, referring esp. to occupation, habit, or association: gamester; songster; trickster. [Middle English; Old English -estre, c. Middle Dutch -ster, Middle Low German -(e)ster] ster. sterling. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.