【Irritable】 , 【fractious】 ,  【peevish】 ,  【snappish】 ,  【waspish】 ,  【petulant】 ,  【pettish】 ,  【huffy】 ,  【fretful】 ,  【querulous】  apply to persons or to their moods or dispositions in the sense of showing impatience or anger without due or sufficient cause.

【Irritable】 implies extreme excitability of temperament, often associated with or arising from fatigue or physical or mental distress, that makes one exceedingly easy to annoy or difficult to please.

【Fractious】  carries a stronger implication of willfulness or of unruliness than  【irritable】 , and although it also implies extreme excitability, it suggests even greater loss of self-control; the term is often applied to animals as well as to persons.

【Peevish】 implies childish irritability and a tendency to give expression to petty complaints or ill-humored trivial criticisms.

【Snappish】 implies irritability or sometimes peevishness that manifests itself in sharp, cutting questions, comments, or objections that discourage conversation or sociability.

【Waspish】 stresses testiness rather than irritability, but it implies a readiness to sting or hurt others without warrant or without sufficient warrant.

【Petulant】 usually suggests the sulkiness of a spoiled child as well as peevishness and capricious impatience.

【Pettish】 implies sulky or childish ill humor (as of one who is slighted or offended).

【Huffy】  also implies a tendency to take offense without due cause, but it suggests more of a display of injured pride than  【pettish】 .

【Fretful】 implies irritability and restlessness that may manifest itself in complaints or in a complaining tone of voice, but often is merely suggested by a lack of ease and repose.

【Querulous】 implies an often habitual discontent that manifests itself in whining complaints or in fretfulness of temper; it often also suggests petulance.