excitable, fickle, fidgety, frivolous, highly strung, jumpy, lively, nervous, playful, restive
calm, composed, demure, laid-back, placid, relaxed, sober, staid, steady, unexcitable, unfazed (informal) unflappable, unruffled
English Collins Dictionary - English synonyms & Thesaurus
1 adj If you describe a person or animal as skittish, you mean they are easily made frightened or excited.
The declining dollar gave heart to skittish investors.
2 adj Someone who is skittish does not concentrate on anything or take life very seriously.
...his relentlessly skittish sense of humour.
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