An irrelevance, since the word used in the puzzle is not 'spastic'; it is a verb which Chambers explicitly classifies only as 'slang'. The other word that you refer to is shown by Chambers as 'offensive, often taboo'; a similarly altered form is explicitly shown as 'offensive slang'.
To arbitrarily ban words based on their etymology would surely rule out 'hysterical' and 'snafu' for starters.