The word winterising is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 18
Highest Scoring Words With Friends™ Plays In The Letters winterising
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Seven Letter Word Alert: (25 words)
igniter, ignites, interns, intwine, nesting, reining, renting, resting, rinsing, stewing, stinger, tensing, tiering, tinners, tinnier, twiners, twinges, twining, wingers, winiest, winners, winters, wiriest, wirings, writing