One's message of dismay about gripping device? (5)
I believe the answer is:
gismo
'device?' is the definition.
(gismo can mean any device or gadget)
'one's message of dismay about gripping' is the wordplay.
'one's' becomes 'I's' (Roman numeral).
'message of dismay' becomes 'OMG' ('oh my god' might be said in dismay).
'about' is a reversal indicator.
'gripping' is an insertion indicator (inserted letters are gripped).
'omg' in reverse letter order is 'gmo'.
'is' going inside 'gmo' is 'GISMO'.
(Other definitions for gismo that I've seen before include "Gadget (colloq.)" , "Doofer" , "Device of American" , "Ingenious gadget" , "Thingumajig - gadget" .)