Open English Wordnet
Adjectives
(a)perceptiblecapable of being perceived by the mind or senses“a perceptible limp”, “easily perceptible sounds”, “perceptible changes in behavior”, “a perceptible sense of expectation in the court”
(s)detectable, perceptibleeasily seen or detected“a detectable note of sarcasm”, “he continued after a perceptible pause”