symp·tom 
(s
ĭm
t
əm, s
ĭmp
-)
n.1. An indication of a disorder or disease, especially a subjective one such as pain, nausea, or weakness.
2. A characteristic sign or indication of the existence of something else: drought and erratic rainfall as symptoms of climate change.
[Middle English sinthoma, symptom of a disease, from Medieval Latin sinthōma, from Late Latin symptōma, from Greek sumptōma, sumptōmat-, a happening, symptom of a disease, from sumpiptein, sumptō-, to coincide : sun-, syn- + piptein, to fall; see pet- in the Appendix of Indo-European roots.]
symptom·less adj.